I need to have a fully working C program, There are five data (plain text) files, namely, the students.txt, courses.txt, registrations.txt, criteria.txt, and performances.txt that keep information. Student file keeps the information about students such as the student number, name, surname, and department in abbreviated form. Course file keeps the information about courses such as the course code and course title. Criteria file keeps the information about course assessments such as the course code, course credit value, homework, lab, quiz, midterm, and final percentages. Registration file keeps the information about the students registrations such as the student number, academic year, semester, and course code. Performance file keeps the information about the students performances such as the student number, course code, and performances.
Below explanations are given for better understanding of the file formats (contents).
A sample line from the student file is 194162 VIANNEY DUSHIME ECE, where 194162 is the student number, VIANNEY is the student name, DUSHIME is the student surname, and ECE is department name.
A sample line from the course file is ENGL121 ENGLISH I, where ENGL121 is the course code and ENGLISH I is the course title.
A sample line from the registration file is 194162 201920 1 MATH101, where 194162 is the student number, 201920 stands for the 2019-20 academic year, 1 stands for Fall, and MATH101 is the course code.
A sample line from the criteria file is CHEM104 4 25 30 45, where CHEM104 is the course code, 4 is the course credit value, and the rest of the line 25 30 45 stands for 25% lab, 30% midterm, 45% final. To keep assessments simple, there are only three performance measures for all courses. For mathematical courses, there is midterm-1, midterm-2, and final exams. For physics and chemistry, there is a lab, a midterm, and a final. For English language courses, there is a quiz, a midterm, and a final. For COMP courses, it is either lab or homework, midterm and final exam percentages.
A sample line from the performance file is 194234 CHEM104 55 65 75, where 194162 is the student number, CHEM104 is the course code, and the rest of the line 55 65 75 stands for the performances such as 55 for the lab, 65 for the midterm, 75 for the final.
The general letter-grading policy for all courses is given as A (90-100), A- (85-89), B+ (80-84), B (75-79), B- (70-74), C+ (65-69), C (60-64), C- (55-59), D+ (50-54), D (45-49), D- (40-44), and F (0-39). The numerical grades for A-through-F are 4.0, 3.7, 3.3, 3.0, 2.7, 2.3, 2.0, 1.7, 1.3, 1.0, 0.7, and 0.0, respectively.
For instance, the student 194234 above collected 67 in CHEM104 and earned letter grade C+.

I will upload the data files later on.