Exchange Values of Two Variables in C Using Function with Example

Introduction

In this tutorial, you’ll learn how to exchange the values of two variables in C using a function. This is done by using call by reference, which allows us to modify the original values of variables from within a function.

---

C Program to Exchange Values of Two Variables Using Function

#include <stdio.h>

void Exchange(int *a, int *b) {
    int temp;
    temp = *a;
    *a = *b;
    *b = temp;
}

int main() {
    int x, y;

    printf("Enter value of x: ");
    scanf("%d", &x);

    printf("Enter value of y: ");
    scanf("%d", &y);

    printf("Before Exchange: x = %d, y = %d\n", x, y);

    Exchange(&x, &y);

    printf("After Exchange: x = %d, y = %d\n", x, y);

    return 0;
}

---

Explanation

• The Exchange function takes two pointers as arguments.
• It uses a temporary variable to swap the values of *a and *b.
• In main(), we pass the addresses of x and y to the Exchange function.
• This demonstrates call by reference, allowing us to modify the original variables.

---

Sample Output

Enter value of x: 5  
Enter value of y: 10  
Before Exchange: x = 5, y = 10  
After Exchange: x = 10, y = 5

---

Use Cases

• Fundamental example of using pointers and call by reference in C.
• Basis for more advanced topics like swapping values in sorting algorithms.
• Important in interview questions and academic assignments.