Example: Functions with Student Structures in C

// Functions with Student Structures
#include <stdio.h>
#include <string.h> // For strcpy

// Step 1: Define the Student structure globally (or pass its definition)
struct Student {
    int studentID;
    char name[50];
    float gpa;
};

// Function to print student details (pass by value)
void printStudentDetails(struct Student s) {
    printf("  ID: %d\n", s.studentID);
    printf("  Name: %s\n", s.name);
    printf("  GPA: %.2f\n", s.gpa);
}

// Function to update GPA (pass by reference/pointer)
void updateGPA(struct Student *s_ptr, float newGPA) {
    if (newGPA >= 0.0 && newGPA <= 4.0) {
        s_ptr->gpa = newGPA; // Use -> operator for pointer to struct
        printf("  GPA updated to %.2f for student ID %d\n", newGPA, s_ptr->studentID);
    } else {
        printf("  Invalid GPA value.\n");
    }
}

int main() {
    // Step 2: Declare and initialize a student
    struct Student s1 = {101, "Alice Wonderland", 3.80};

    printf("--- Original Student Details ---\n");
    printStudentDetails(s1); // Call function by value

    printf("\n--- Updating GPA ---\n");
    updateGPA(&s1, 3.95); // Call function by reference (pass address of s1)

    printf("\n--- Updated Student Details ---\n");
    printStudentDetails(s1); // Print updated details

    // Example of another student
    struct Student s2 = {102, "Bob Builder", 3.10};
    printf("\n--- Bob's Original Details ---\n");
    printStudentDetails(s2);
    updateGPA(&s2, 2.50);
    printf("\n--- Bob's Updated Details ---\n");
    printStudentDetails(s2);

    return 0;
}