In ICS 212: Program Structure, a course I took in Spring 2024, I developed a student record management system using the C programming language. The goal was to create a terminal-based application that could read, display, edit, and persistently save student records stored in a binary file. This hands-on project helped me solidify my understanding of C structures, file I/O, modular functions, and robust user input validation.
The program interacts with a binary file named students.data, which stores records of student information in the form of a Student struct. Each record includes the student number, first and last names, age, and GPA. These structs are defined in an external header file, student.h, to keep the data model modular and clean.
The application begins by opening the binary file for reading and writing:
filePointer = fopen(fileName, "rb+");
If the file cannot be opened, the program exits gracefully with an error message:
if(filePointer == NULL){
printf("File \"%s\" could not be opened. \n", fileName);
exit(1);
}
Records are displayed using a loop with fread():
while (fread(&studentX, sizeof(Student), 1, filePointer)) {
printStudent(studentX);
}
The printStudent() function formats and displays each record in a table, making it easy for users to visually browse the data:
void printStudent(Student studentX){
printf("%6d %10s %10s %3d %3.1f \n",
studentX.number,
studentX.first,
studentX.last,
studentX.age,
studentX.gpa);
}
The user is prompted to choose a specific record to edit by entering its index. Input is validated using:
int validateRecordNumber(int maxRecords);
This function ensures the record number is within bounds and discards any invalid input using a buffer-clearing loop:
while (getchar() != '\n');
Once a valid record is selected, the program uses fseek() to navigate to the correct byte offset:
fseek(filePointer, (recordNumber - 1) * sizeof(Student), SEEK_SET);
The user chooses which field to edit via the getOption() function. This validates the input to allow only ‘f’ (first name), ‘l’ (last name), ‘a’ (age), or ‘g’ (GPA):
char getOption() {
...
if (option != 'f' && option != 'l' && option != 'a' && option != 'g') {
...
}
}
The editRecord() function then uses a switch statement to call getstring() for names, or scanf() for numerical fields:
void editRecord(Student *studentX, int recordNumber, char option) {
...
case 'g':
printf("Enter GPA: ");
scanf("%lf", &studentX->gpa);
break;
}
After editing, the updated struct is written back to the file using fwrite():
fseek(filePointer, (recordNumber - 1) * sizeof(Student), SEEK_SET);
fwrite(&studentX, sizeof(Student), 1, filePointer);
Proper cleanup ensures that the file is closed correctly, with user feedback depending on the return status:
fileClosed = fclose(filePointer);
if(0 == fileClosed){
printf("The file \"%s\" was successfully updated.\n", fileName);
}
This project taught me how to manage binary file data, handle user input safely, and build modular C programs using multiple source files and headers. I learned to think in terms of data offsets and memory layout, and I gained experience implementing validation loops, formatted output, and error handling.
To debug and experiment with logic, I also used AI tools like ChatGPT for quick prototyping and explanation of standard library functions, especially during asynchronous development. Completing this project gave me confidence in using C to build real-world, file-backed applications that simulate simple database functionality.