C Program to Calculate Total and Average Marks of 5 Students in 3 Subjects Using Nested Loops

Introduction

In C programming, nested loops are extremely useful for managing multi-dimensional data like student marks in multiple subjects. In this tutorial, we’ll write a C program to calculate the total and average marks of 5 students across 3 subjects using nested for loops.

This program is ideal for learning how to process structured data like a table or matrix using arrays and loops.

---

Problem Statement

Create a program that accepts marks for 5 students, each with 3 subjects. The program should calculate the total and average for each student using nested for loops.

---

C Program to Calculate Average and Total

#include <stdio.h>

int main() {
    int marks[5][3];
    int total;
    float average;

    // Input marks for 5 students and 3 subjects
    for (int i = 0; i < 5; i++) {
        printf("Enter marks for Student %d:\n", i + 1);
        for (int j = 0; j < 3; j++) {
            printf("Subject %d: ", j + 1);
            scanf("%d", &marks[i][j]);
        }
    }

    // Calculate total and average
    for (int i = 0; i < 5; i++) {
        total = 0;
        for (int j = 0; j < 3; j++) {
            total += marks[i][j];
        }
        average = total / 3.0;
        printf("Student %d - Total: %d, Average: %.2f\n", i + 1, total, average);
    }

    return 0;
}

---

Explanation

• 2D Array: Used to store marks of 5 students and 3 subjects.
• Nested for loops: Outer loop handles students, inner loop handles subjects.
• Calculation: Total is the sum of 3 subject marks; average is total divided by 3.

---

Sample Output

Enter marks for Student 1:
Subject 1: 75
Subject 2: 80
Subject 3: 70
...
Student 1 - Total: 225, Average: 75.00
...

---

Why This Program is Important

• Helps understand nested loops
• Great for handling structured data
• Foundation for multidimensional array operations in C

Conclusion

This C program to calculate average and total of 5 students using nested loops is a practical exercise for beginners. It reinforces loop control, 2D array handling, and logic building in C.