Introduction

The core focus of Outcome-Based Education (OBE) education philosophy is on students’ learning ability. Students’ learning outcomes are affected by teaching design and implementation of the teaching process1. Conceive–Design–Implement–Operate (CDIO) includes four parts: conception, design, implementation, and operation. CDIO enables students to actively participate in the project process2. While enabling students to master theoretical knowledge, it can also improve students’ analytical understanding and practical abilities, while cultivating innovative awareness. The CDIO engineering model is an effective way to implement OBE. The OBE-CDIO education philosophy is student-centered, guided by training goals and graduation requirements, and promotes reverse reform of teaching goals, content, methods, and evaluation modes of courses. Sustainable development emphasizes the coordination and unity of economic, environmental, and social aspects, and the OBE-CDIO combination model is consistent with this concept3,4. The OBE-CDIO model focuses on comprehensively cultivating students’ qualities and abilities, giving them the ability to conceive, design, implement, and operate product systems in enterprise and social environments. At the same time, the OBE-CDIO model also focuses on continuous improvement and optimization of education to adapt to the changing social and economic environment5.

China's engineering education professional certification started in 2006 and became a full member of the Washington Accord in 20161. In China, some universities have begun to try to introduce the OBE and CDIO models into engineering education through reforming curriculum design, experiments, internships, etc. These universities continuously optimize the educational process by drawing on the concepts and methods of the OBE and CDIO models. Engineering education professional certification plays an important role in promoting undergraduate training1,6. Based on the OBE and CDIO education models and combined with the emerging changes in engineering education, Chen Weiping proposed the 3I-CDIO-OBE talent training model of engineering education in China, which fully embodies the attributes of general education, professional education, and innovative education in engineering teaching7. Lu Aichen proposed a project-oriented CDIO open maker classroom and practical teaching system that aimed to meet the needs of professional fields through reverse-designed teaching projects and project-oriented and project-driven teaching, and realized the creation of open and conversational classrooms8. Cai Meiling put forward the idea of teaching reform in combination with the educational concept of engineering education professional certification, and explored the reform of teaching with consideration of three aspects: teaching content, teaching mode, and teaching evaluation9. Liu Jie put forward the concept of OBE to formulate teaching goals, optimize teaching content, adopt a mixed teaching mode for offline and online, and build a sustainable improvement assessment and evaluation system of the teaching process10. Shen Zhenqian proposed to innovate the experimental teaching carrier, guided by professional development, reconstruct the experimental teaching content, guided by engineering applications, and develop an experimental teaching design, guided by engineering problems, so as to improve students’ practical engineering ability and better meet the social demand for talent training11. Lin Fei introduced a six-element fusion method of “project leading–flipping teaching–personality training–task driving–pair programming–process assessment” to design and implement the experimental teaching of programming, effectively improving teaching quality12. In summary, the application of OBE-CDIO in programming design experiment courses can help to cultivate students' programming ability and problem-solving skills, improving their quality and engineering practice ability. At the same time, this model also requires teachers to change their roles, pay attention to students' learning progress and difficulties, and provide targeted guidance and support. Through the continuous optimization of the content and methods of the experimental course, the experimental teaching can better meet the needs of students’ learning and development. However, there are still some shortcomings in relevant research, such as the lack of close integration between experimental teaching and engineering practice, the need to strengthen interdisciplinary team cooperation, and the need to improve the innovation of teaching methods and means. These deficiencies limit the effect of experimental teaching, which needs to be further reformed and perfected.

Engineering education certification standards are evaluation and accreditation standards for engineering education quality, aiming to ensure that engineering education meets industry standards and future career development needs. Engineering certification standards usually include assessments of students’ knowledge, skills, and abilities, as well as assessments of educational institutions’ teaching resources, faculty, curriculum design, etc. Based on the above research and according to the OBE and CDIO concepts and in line with engineering education certification standards, this paper organized the implementation of a C Language Programming experimental course based on the “student-centered” teaching concept. This teaching process guides students to learn independently through four stages: conceptualization, design, implementation, and operation, allowing them to integrate their knowledge and apply it to practical problem-solving. The main contributions of this paper are as follows:

  1. (a)

    According to the engineering education accreditation standards and OBE-CDIO philosophy, a complete content system, knowledge structure, and experimental modules for C language programming design were designed. A large number of teaching resources, including micro-videos and experimental cases, were created, along with a sustainable assessment and evaluation system.

  2. (b)

    A wide range of teaching methods, such as online experiment platforms, micro-video teaching, and team experiments, were adopted. These methods were integrated with research, competitions, and enterprise practices to enrich the teaching methods and solve common problems, such as single teaching methods, student level differences, and the need for personalized tutoring. This approach motivated students and comprehensively improved their practical abilities.

  3. (c)

    The teaching process emphasized a student-centered approach and project-based learning, combining theory with practice to form a programming experimental teaching model that meets the requirements of sustainable development in an engineering education context. This model effectively promoted the cultivation of students' programming practice ability and innovation ability.

Through the above innovative contributions, teaching reform comprehensively considers the improvement of curriculum concept, curriculum design, curriculum implementation, curriculum operation, etc. Through the practice of teaching process reconstruction, teaching content organization, and teaching method integration, it achieves the purpose of optimizing the experimental teaching organization mode and improving students' practical ability, innovation ability and comprehensive application ability of knowledge.

New requirements for experimental teaching of program design courses in engineering education

The experimental teaching reform of C Language Programming courses based on engineering education concepts aimed to integrate new teaching concepts and teaching methods and improve students' learning through new concepts, new technologies, and new communication platforms. Engineering education professional certification requires professional curriculum system. The certification of engineering education requires the establishment of professional curriculum system, curriculum teaching, staffing of teachers and allocation of school conditions to focus on the core task of achieving students' graduation ability, and emphasizes the establishment of continuous improvement mechanism to ensure the quality and vitality of professional education. In the implementation of the concept of engineering education, it is necessary to guide students to start by thinking about software engineering, undertake the demand analysis and system design of the project, and then carry out program coding and system debugging, before finally completing the process, from design to development of the project.

The Teaching Process is Student-centered

Engineering education certification standards place importance on the requirements and training goals of students, and emphasize that education and teaching should be student-centered13. A C Language Programming course is the first point of entry for students majoring in computer science, and it is an important foundation for entering the field. Teachers must give students effective guidance in the teaching process, focus on the students' learning process and effect, and measure and promote the outcomes of their teaching, as shown in Fig. 1. Taking into account the developmental needs of students as individuals, it is necessary to respect the differences of each student and give students equal opportunities to learn.

Figure 1
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Student-centered instructional design.

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Greater emphasis on ability improvement-oriented teaching goals

The teaching goal of C Language Programming courses is to improve students’ ability to analyze problems, their coding and solving, and their thinking about software engineering. The teaching should be goal-oriented, and teachers should consider the improvement of ability and quality development as the fundamental requirement of the teaching process14. At the same time, there should be an emphasis on training students to use this knowledge to analyze, research, and solve problems.

The teaching model requires continuous improvement

Engineering education requires a continuous improvement mechanism and implementable measures to improve the quality of education and teaching. It emphasizes the continuous improvement and refinement of assessment mechanisms for teaching effectiveness, feedback mechanisms for tracking teaching outcomes, etc., to ensure that course teaching goals do not deviate from professional training directions and lay a solid foundation for students to meet graduation requirements15. Based on the assessment and evaluation of the teaching process, teachers and students must make improvements accordingly. This relies on the formulation of relevant policies to ensure that teaching evaluation and teaching improvement can be carried out.

Course reconstruction based on the OBE-CDIO model

The experimental teaching reform of C Language Programming based on the OBE-CDIO concept emphasizes students' subjective initiative in exploring knowledge, discovering knowledge, and constructing knowledge, which is helpful to cultivate students’ ability to actively think and solve practical problems.

Analysis of the learning situation

Taking the computer science and technology major of grade 2021 in Gansu University of Political Science and Law as an example, this study administered surveys to 123 students. The survey results are shown in Fig. 2.

Figure 2
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Analysis of the student surveys.

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  1. (a)

    Knowledge characteristics

None of the students had ever learned programming, and 53% had little prior exposure to computers. In the actual teaching process, it was found that the proportion of students with weak foundations to good foundations in the class was close to 1:11, and their basic programming ability was relatively weak in general. Further investigation found that a total of 41% of the students had a good mathematical foundation, and 85% of the students were in the general level and above, indicating that most of the students had the mathematical foundation to master programming.

  1. (b)

    Ideological characteristics

Research and discussion show that students lack professional knowledge and professional ideas have not yet been formed. At the same time, 80% of the students had a clear goal for this course, and the students' learning consciousness and self-discipline were high. The study in the following semester also verified that most of the students could take the initiative to complete the tasks assigned by the teacher.

  1. (c)

    Psychological characteristics

The surveyed students had experienced three years of high school learning, and were accustomed to passive acceptance of knowledge and a lack of scientific learning methods. According to the survey, 65% of the students said they were worried about the subject. C Language Programming has adopted the on-computer examination method since 2017, which is a challenge for freshmen. Faced with a series of grammatical structures and complex algorithm designs, students are often afraid of finding the course difficult, so their learning enthusiasm needs to be improved.

The above survey results showed that, faced with clear learning goals but also a fear of difficulties, the traditional full-classroom teaching model is completely unfit for today’s students’ learning. We aimed to solve the problem of centering students in the redesign of the teaching model to help students overcome any difficulties.

Establish the goals and positioning

Before the implementation of classroom teaching, it is necessary to clarify the teaching goals, and at the same time to analyze the learning situation of the teaching object.

Overall conception of positioning

The overall conception of the course based on the OBE-CDIO mode is the orientation that determines course implementation and the final results.

C Language Programming is a basic compulsory course for computer-related majors. It is basic and introductory, representing a public platform in the architecture of the computer undergraduate training program. It is the first language for students of related majors to learn and lays a solid foundation for further learning of C++, Java, Python, Windows programming and others, and for mastering project development. C Language Programming must be practical, as theoretical learning does not support the development of students' independent programming ability. Students must combine theory and practice closely to master the theoretical basis and the ideas and methods of program design, and the application of independent design and writing programs16. Therefore, it is necessary to reform the experimental teaching of C programming course.

Dynamic adjustment of course goals

The teaching goals of the courses should be dynamically adjusted with societal changes and the strategic adjustment of national subject planning. As the basic core of computer-related majors in colleges and universities, C Language Programming courses play a vital role in students' professional learning and training. Students are required to have mastered skills in program design, development, and testing, and to analyze and solve problems using computational thinking methods. The cultivation goals can be summarized into four categories: knowledge, ability, attitude, and engineering thinking, as shown in Fig. 31,17,18.

Figure 3
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Thinking map of teaching goals.

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Constructing the teaching content system of the course

Based on an accurate understanding of students’ situation, the experimental teaching syllabus was rewritten, the experimental teaching system was reconstructed, and the guiding ideology of steadily and gradually improving students' practical abilities was clarified.

Organization of teaching content

C Language Programming experiments involve a lot of conceptual rules and the use of flexible forms. Before the implementation of the experiment, it is necessary to formulate targeted experimental content according to the outline, select and determine specific experimental topics according to the key points and difficulties of each chapter, pay attention to the flexibility and practicality of the experimental content, start with simple verification experiments, and gradually transition from basic experiments to comprehensive experiments. According to the teaching steps, the knowledge goals of the C Language Programming course was divided into stages, and the logical framework of the teaching content is shown in Fig. 4. With the knowledge logic framework, students can easily understand and master the required knowledge, and teachers can optimize their teaching19,20.

Figure 4
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Content system of the experimental teaching of a C Language Programming course.

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Building the stepped knowledge system

Engineering education emphasizes the application and innovation of knowledge, and builds a knowledge system that can serve training goals. In the design and development of specific experimental projects, the following three requirements need to be met21.

  1. (a)

    The construction of the knowledge system should highlight comprehensive practical ability, so that students can combine theory with practice;

  2. (b)

    The construction of the knowledge system should highlight the development of social industry technology and keep up with the trends of industry technology, so that students achieve a higher technical starting point;

  3. (c)

    The construction of the knowledge system should highlight integration with the professional certification of engineering education, so that students can meet the requirements of the certification index system.

The above requirements reconstruct the experimental content system according to the knowledge, abilities, and quality required for graduation. The pyramidal structure of “knowledge point–module–task–project” was adopted, as shown in Fig. 5. Firstly, the teaching content was organized layer by layer from bottom to top. Secondly, the experimental project was designed according to the goals, and the project was divided into different sub-tasks composed of different modules, and the knowledge points were extracted from the modules. Finally, the teaching was organized from the bottom up, and combined with the three-step experiment type of “verification experiment–comprehensive design experiment–innovative research experiment”, practical teaching was carried out step by step from shallow to deep, so as to connect each unit in the series and complete the experimental project.

Figure 5
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Architecture of C Language Programming experimental teaching.

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Supporting measures to strengthen teaching

According to the characteristics of students majoring in information security, cyberspace security, and computer science and technology, the teaching team explored the law of knowledge formation in the process of teaching and learning, with the aim of continuously improving teaching efficiency.

Integration of individual experiments and hierarchical collaborative experiments

Through the design of hierarchical and differentiated experimental teaching content, we carried out the construction of diversified collaborative experimental teaching methods. The basic experiment was carried out by the students themselves, and the comprehensive design experiment and innovative research experiment adopted the hierarchical cooperative experimental teaching mode22. In addition to the verification and comprehensive design experiments required by the unified requirements, students could choose the improved innovative research experiment projects independently according to their interests. Diversified collaborative experimental teaching was implemented, so that students of different basic levels could be reasonably combined and divided into tasks, and each student could cooperate with others to a certain extent, while also remaining independent.

Integration of teacher teaching and micro-video teaching

The experimental teaching content of C language was organized into modules. Each module was relatively independent and progressive, and each module was decomposed, organized, and constructed according to various aspects of the knowledge points, for which 12 high-quality teaching micro-videos were made, as shown in Fig. 6. Each micro-video lasted for 6–8 min, and elaborate teaching design was carried out around specific knowledge points and difficulties23. In the teaching, on the basis of the teacher’s classroom guidance, the micro-video experiment teaching mode based on knowledge points was further integrated. Students watched and practiced the operation method of programming software through the micro-videos repeatedly, becoming familiar with the basic composition of the program. In class, the teachers gave individual guidance and explanations, communicating with and interacting with the students, giving timely answers to questions and solving difficulties with students, to form a complete teaching loop. This enables students to use fragmented time and watch the videos at convenient times on mobile terminals.

Figure 6
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Structure diagram of micro-video teaching for the C Language Programming experiment.

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Integration of online and offline experiments

The C Language Programming experiment was divided into offline and online forms. The basic verification experiment was based on a network experiment teaching platform that supports remote autonomous experiments. Comprehensive design experiments and innovative research experiments were implemented offline. The network platform not only provided network teaching management functions, but also integrated the online evaluation function of the C language program, as shown in Fig. 7. The online experiment teaching mode was “evaluation to promote learning” and was oriented towards evaluating the effectiveness of learning24.

Figure 7
figure 7

Organizational structure and approach for production–education integration.

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Integration of scientific research and teaching

In view of the requirements to develop students’ innovation ability and engineering practice ability, and from the perspective of knowledge application and discovery, teachers' scientific research results can be returned to teaching. The integration of scientific research and education was adopted to strengthen the cultivation of students' innovative thinking and engineering practice ability. In the teaching process, by showing the teaching team’s involvement in network attack traceability, automatic identification of telecom fraud, automatic detection of botnets, and other scientific research topics, we encouraged students to explore more freely, question and innovate, and cultivate their engineering and innovative thinking. In particular, the students showed interest in the specific application of C language knowledge to national innovation and entrepreneurship projects guided by the team.

Integration of competition and teaching

Subject competition can contribute positively to reform. Combining theory with practice through competition can reflect students’ mastery of knowledge and effectively promote the transformation of teaching results. Competition was introduced into the teaching process. At the same time, students were encouraged to participate in national program competitions such as the “Blue Bridge Cup National Software and Information Technology Professionals Competition” (Blue Bridge Cup) and “UP-TECH Cup National College Students Embedded Design Competition” (UP-TECH Cup). Competition, when co-guided by senior engineers of enterprises and teachers in schools, can promote teaching reform, strengthen practical teaching, and stimulate students' innovative development. Positive competition results can promote learning motivation and professional quality in subsequent projects, laying a solid foundation for academic and career planning.

Integration of production and teaching

The integration of industry and education in programming courses can better meet industrial needs and market development trends, cultivating high-quality students in line with market demands. Based on the idea of demand-driven and industry-academic cooperation, a dual-teacher system was formed between experienced engineers from enterprises and on-campus teachers to jointly build practical teaching courses, experimental textbooks, and laboratories for the integration of industry and education25, as shown in Fig. 7. They worked together to guide students' practical work. Students formed teams of three and independently selected a project, and each group was given a team leader responsible for overall project work arrangements. Through the development of projects, students' programming skills, teamwork, and engineering abilities were cultivated. In addition, through the establishment of characteristic classes and organizing students to undertake professional practice in enterprises during summer vacation, students’ hands-on practical abilities were further enhanced.

Practice of the teaching model based on OBE-CDIO

The teaching team of C Language Programming adopted the concept of engineering education in the experimental teaching practice based on OBE-CDIO, highlighting the combination of curriculum characteristics and students’ learning characteristics, and focusing on cultivating students’ logical thinking ability, stimulating their innovation ability, and teaching students in accordance with their aptitude.

Teaching mode based on OBE-CDIO

The teaching mode based on OBE CDIO organized teaching according to the four steps of “Conceive, Design, Implement, and Operate”. The instructional design process after the reform is shown in Table 126,27.

Table 1 OBE-CDIO experimental project teaching steps and content of each stage.
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Conceive

C Language Programming takes cultivating students’ practical ability in programming as the main teaching goal. The design was considered from the perspective of multiple dimensions, such as perfecting teaching goals, integrating teaching content, improving the teaching mode, reorganizing teaching staff, perfecting teaching materials, changing students' thinking, and resetting assessment and evaluation indicators9,28.

  1. (a)

    In the actual teaching process, teachers should design the teaching content to support students to achieve the training goals required by graduation. It is necessary to consider the acceptability and learning needs of students at different levels, and design a comprehensive teaching resource library.

  2. (b)

    Students’ autonomy, initiative, and creativity should be emphasized in choosing appropriate teaching methods, mobilizing students' enthusiasm, stimulating students' interest in learning, and promoting active learning.

  3. (c)

    The focus should be on continuous improvement, reforming evaluation methods, establishing a quality monitoring mechanism to track and evaluate the teaching process, diagnosing existing problems, and providing a basis for continuous improvement of teaching content and teaching methods.

Design

This was based on the concept of results-oriented education, which is teaching reform guided by students' learning outcomes, allowing students to develop project proposals, complete project planning, and conduct case studies.

Before class, teaching was based on micro-videos and case materials. In class, online teaching platforms, case explanations, group discussion, and other forms of teaching were used to guide students to analyze and solve problems, carry out concrete transformation, and improve their computational thinking ability and software development ability. After class, programming training was conducted to guide students to explore cutting-edge technologies.

Implement

Because the educational concept of OBE-CDIO emphasizes the cultivation of application-oriented talents and focuses on the cultivation of students’ information ability, operation ability, team communication, collaborative learning ability, and creative ability, it is necessary to replace traditional teaching modes with diversified teaching modes.

Diversified teaching mode

A variety of teaching modes were adopted, such as the integration of individual independent experiments and hierarchical collaborative experiments, the integration of in-person teaching and micro-video teaching, the integration of online and offline experiments, the integration of science and education, the integration of competition and teaching, and the integration of production and teaching. We carried out the comprehensive application of case teaching methods, situational teaching methods, experiential teaching methods, flipping methods, discussion methods, and other specific methods to organize classroom teaching.

Construction of modular teaching resources

Experiments related to C Language Programming can be divided into basic experiments and design experiments. In the Wanwei examination system, a verification bank of more than 800 questions was set up, and 92 design cases under six categories were built into the design experiment.

The experimental teaching content of the C Language Programming course was organized into 15 teaching micro-videos, each of which was relatively independent and progressive. Each micro-video was organized around the nine aspects of the knowledge points, which reflected the three-dimensional model of the knowledge points.

Professional teaching team

In order to strengthen the experimental teaching level, we adjusted the original teaching team and re-established the experimental teaching team for the C Language Programming course, as well as adding three doctors into the teaching team. At the same time, in cooperation with ETIME (Chengdu Eteng Creative Intelligent Technology Co., LTD) and other teaching institutions, we hired two enterprise teachers to join the experimental teaching. The enterprise teachers were mainly responsible for making experimental plans and designing comprehensive experiments. The construction of this professional teaching team not only achieved the practical application of program design knowledge, but also cultivated the ability of students to write programs independently.

Information-based teaching method

In the last 5 years, Gansu University of Political Science and Law has built six multi-functional intelligent comprehensive laboratories, equipped with more than 600 experimental booths, covering an area of about 1100 square meters. An integrated teaching system for four programming languages, including C language, has been installed, including online learning, experiments, exercises, examinations, and other integrated functions. The new laboratory environment, new technology, and new facilities have greatly improved the environment and conditions of practical teaching of programming, and have provided a guarantee for the continued experimental teaching of the C Language Programming course. Before and during teaching, micro-video, online test platforms, and other teaching modes have been introduced to create an improved learning environment. After class, the author answered student questions through Wechat group, QQ group, and an online experimental message platform, achieving significantly improved communication with the students.

Refining the process of evaluation

A multi-dimensional evaluation mechanism was implemented in the teaching process, and the evaluation mode of the experimental system is shown in Fig. 8. The time dimension encompassed both process and final assessments, the content dimension took into account both verification experiments and comprehensive experiments, and the mode dimension employed peacetime process assessment and end-of-term comprehensive practice. For confirmatory experiments, the experimental system was used for automatic scoring. For comprehensive design experiments, the comprehensive three-dimensional evaluation system was adopted, which combined individual assessment and team assessment, teacher evaluation, and student mutual evaluation. The evaluation indicators covered team communication and cooperation, individual independent operational ability, team member mutual evaluation, teacher evaluation scope, etc. The results of students after completing learning tasks were obtained based on study notes, problem-solving reports, program codes, speeches and explanations, tests and exams, discussions or debates, answers and exchanges, discipline competitions, and other forms.

Figure 8
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Wanwei fully automatic experimental and assessment platform for C Language Programming.

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According to the above evaluation system, student and teaching effects could be evaluated in different ways, such as monthly evaluations, mid-term evaluations, final evaluations, etc., to grasp the teaching design and implementation effects and student learning effects at any time, so as to provide feedback and continuous improvement of future teaching design.

Operate

Students engaged in group discussions, clarifying the division of labor, and produced a presentation in the form of a PPT report after consulting materials to fulfill the expansion function. The team’s ability to collaborate, engage in engineering practice, and demonstrate their progress during the implementation of the project was evaluated through on-site defense and demonstration. Once the experimental defense was complete, students composed an experiment report that encompassed the program's design ideas, flowcharts, precautions, and personal experiences. Instructors responded to inquiries and summarized the project, assigning additional assignments as necessary.

Teaching case of the course based on the OBE-CDIO mode

The experiment took writing the program of the “student information management system” as a case, and connected the learned knowledge from the superficial to the profound in the form of successive layers, and finally formed a complete and comprehensive experiment item. This method of distribution of experimental items allowed students to gradually connect the knowledge points.

Knowledge decomposition based on OBE-CDIO

In writing a simple student score management system, the experimental content was closely linked to the knowledge points in the design, cultivated students’ initial independent analysis and design ability, and supported students to understand the specific process and realization of application program design to solve practical problems and master the basic norms of C language for program design. The specific knowledge points are broken down in Fig. 928. Through the experiment training, students focused on C Language Programming, function design, algorithm design, and program debugging methods, initially mastering the system development process of the problem analysis, system design, program coding, testing, and other basic methods and skills.

Figure 9
figure 9

Decomposition of knowledge points in the student information management system.

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Practice teaching process of the case

Based on the requirements of CDIO engineering education in terms of conception, design, implementation, and operation of the four stages, combined with the evaluation system of the OBE engineering education model, the integrated teaching process was established as shown in Fig. 1029.

Figure 10
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Instructional design process based on OBE-CDIO.

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Conceive stage

Before class, the teachers arranged projects and micro-videos on the learning platform. The experiment was carried out in pairs, and the students discussed and designed the project in extracurricular time. The design schemes submitted by the students were classified by the teacher, who selected 3–4 representative groups of schemes and organized the students to explain them in class. The teacher guided the students to question and analyze together to improve the solution. In the process of explaining the scheme, the teacher first encouraged other students to ask questions. If the students could not find the answer to the problem, the teacher would give corresponding prompts, guide the students to determine the problem, cultivate the students’ ability to determine the problem independently, and finally guide the students to solve the problem step by step30.

In the process of implementing this approach, the enthusiasm of every student should be fully mobilized. In view of the problems in the scheme presented by students, questions should be asked to all students in the class to encourage active participation. At this stage, students needed to conceive the functional module diagram of the student achievement management system, as shown in Fig. 11.

Figure 11
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Function module diagram of student achievement management system.

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Design stage

The main task of the experimental design stage was to accurately describe the idea with the model, so as to convert the idea into the C language program in the realization stage. The teacher explained and guided the students to design the system development process. According to the teacher’s problem-solving ideas and processes, the students sorted and combined the sub-module program segments, spliced them into a complete program that could run, and completed the construction of the thinking model. Under the guidance of the teacher, the students divided the system into modules and obtained the working flow chart of the system, as shown in Fig. 1230.

Figure 12
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Workflow chart of the student information management system.

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Implementation stage

The work of the implementation stage mainly included coding, debugging, running, and other operations of the code. The biggest problem in the debugging program was the modular design and debugging method of the program; therefore, focusing on training students to use modular programming methods, problem analysis, and problem-solving skills, and to learn to step by step, was important. Teachers in the classroom could find and guide students in the process of debugging difficulties. Students who did not complete the task in time could continue to improve the program and reflect on the experience after class. Before the end of the class, the teacher summarized the knowledge and ability requirements of the system design and implementation, and carried out innovative application ideas for the knowledge points for after-class thinking expansion.

Operate stage

The work in this stage was mainly for teachers to organize students to demonstrate in groups, defend, summarize, and improve, and write the experiment report. Each group displayed the experimental results separately, and the teacher raised relevant questions for any student in the group, such as how to modify parameters in order to achieve a certain effect, so as to prevent only one student in the group contributing. The teacher guided the students to evaluate each other on the experimental results, so as to deepen the students’ interpretation of the program and improve the students’ programming and reading ability through feedback.

Continuous improvement

After the completion of the experiment, the teachers were able to find problems in the teaching, make timely improvements to the experiment plan and experiment content, perfect the teaching organization process, continuously improve the teaching design, and enhance teaching effects.

During the teaching process, questionnaires, teacher-student discussions, and student self-evaluation of various goals were used to obtain students’ evaluations and suggestions for the experiment content, teaching modes, and assessment methods.

At the end of the semester, teachers summarized the whole semester’s teaching, evaluated their teaching goals, and reflected on teaching quality by integrating students' assessments, self-evaluations, and the school teaching evaluation system.

Effect of course teaching reform

The online and offline integration teaching mode of the C Language Programming course based on the OBE-CDIO mode was reformed for two consecutive years in Gansu University of Political Science and Law, for students majoring in information security, cyberspace security, and computer science and technology in grade 2021 and grade 2022. More than 500 students participated in the reform, and acceptable teaching results were achieved.

Analysis of the achievement of course goals

Students had clearer learning goals and stronger learning initiative. Students of all majors significantly improved their abilities in writing programs and solving practical engineering problems, as well as cultivating graduate innovation ability.

Taking the computer science and technology major as an example, the experimental results of students in grade 2023 increased by 8% compared with those in grade 2021, while the total score, including the theoretical results, increased by 6%. There were four goals corresponding to this in the engineering certification outline31, and a radar chart of the degree of achievement of the goals is shown in Fig. 13. Students have made remarkable progress in knowledge, ability, quality and engineering thinking through C programming course. Students have a deep grasp of the basic grammar and programming ideas of C language, and their practical operation ability has also been improved. More importantly, students' teamwork, communication skills and engineering thinking have been significantly enhanced, and they are able to apply their knowledge to solve practical problems and design and implement small systems. These results show that the course has achieved remarkable results in improving students’ attitude and engineering thinking.

Figure 13
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Radar chart of the achievement of goals.

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Analysis of students' self-evaluation questionnaire

At the end of the semester, self-evaluation questionnaires were issued to students to assess their consolidation of the theoretical foundation, independent learning ability, teamwork ability, and comprehensive practical design ability32.

A comparison of the students of the same major in grade 2023 and grade 2021 is shown in Table 2 and Fig. 14. After adopting the multi-method integrated experimental teaching method based on OBE-CDIO, the students' self-evaluation was significantly improved in all areas, but especially in terms of personal programming ability and comprehensive practical ability.

Table 2 Statistical table of students’ self-evaluation.
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Figure 14
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Comparison of students’ self-evaluation of practical ability before and after the experimental teaching reform.

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Analysis of course output

Under the OBE-CDIO teaching mode, students’ self-inquiry learning ability was significantly enhanced, their ability to analyze and solve problems was improved, and their innovation consciousness and innovation ability were increased. Some students participated in the Blue Bridge Cup and UP-TECH Cup, and achieved excellent results. Awards earned by students participating in competitions in the past three years are shown in Table 3 and Fig. 15. From the point of view of the number of awards, students have repeatedly won good results in various competitions, and the number of awards has increased year by year, which not only reflects the students’ increasing mastery of programming ability, but also reflects the students’ active participation in discipline competitions. From the perspective of award level, the number of national awards won by students in 2021, 2022 and 2023 is 2, 4 and 10 respectively, and more and more students can win high-level awards in the competition, indicating that students' skill level and comprehensive quality in the professional field have been greatly improved.

Table 3 Students’ awards of competitions in the past 3 years.
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Figure 15
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Trend chart of the number of awards won by students in programming competitions in the past 3 years.

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Based on these results, the teaching team applied for an industry-university cooperative education project from the Ministry of Education, and a project of higher education teaching achievement cultivation in Gansu Province.

Discussion and conclusion

Under the background of engineering education professional certification, the OBE education concept of “output-oriented” has been paid more and more attention. In the context of professional certification in engineering education, the “C Language Programming” educational model rooted in the OBE-CDIO framework aims to ignite students’ passion for learning and exploration while bridging the gap between theory and practice through project-based learning. According to the OBE-CDIO educational concept, this paper explores the experimental teaching reform of C programming course from the perspectives of teaching goals, design, mixed teaching methods and evaluation strategies. The scientific integration of diverse teaching activities and methods, guided by the OBE concept, effectively addresses challenges such as monotony in teaching methods, scarcity of experimental resources, and student-level disparities, thereby fully harnessing students' learning enthusiasm and tapping into their potential. The proposed experimental teaching approach is marked by its emphasis on practical engineering projects, significantly enhancing students' professional skills to align with the demands of burgeoning technology industries and novel software developments. In comparison to other methods, this approach more aptly satisfies the genuine requirements of engineering education, refining students' practical and innovative abilities. Additionally, the student-centric teaching reform encourages students' initiative and creativity, fostering their independent learning and teamwork skills. Consequently, this teaching reform not only boasts significant advantages, but also contributes to cultivating high-caliber talents that are well-suited for the evolving needs of the engineering field.

Although the experimental teaching reform practice has made some achievements in recent years, there are still some limitations, such as: the connection between online and offline teaching is not smooth enough, the number of practical positions provided by enterprises is insufficient, and the level of students to participate in competitions needs to be improved. In the future work, it is necessary to further explore and reform students' industrial practice ability, strengthen the lack of supervision in the implementation of offline independent development projects, balance personalized training and teaching efficiency, and constantly improve the experimental teaching effect of programming courses based on the OBE-CDIO model.

Ethics statement

This study was approved by the ethics committee of the affiliated Gansu University of Political Science and Law. There is no experiment on humans and/or the use of human tissue samples in this study. All methods in the study were carried out in accordance with relevant guidelines and regulations, all experimental protocols were approved by a named institutional and/or licensing committee, and informed consent was obtained from all subjects and/or their legal guardian(s).