C Program to Interchange Two Numbers with Example

If you’re learning C programming, understanding how to interchange two numbers is one of the first key concepts. It teaches you how variables work, how to use a temporary variable, and how logic flows in a program. This tutorial walks you through a simple C program to swap two numbers, its logic, and why it matters in programming basics.

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What Does Interchanging Mean?

Interchanging (or swapping) two numbers means switching the values between two variables. For example:

Before:
a = 10, b = 20
After interchanging:
a = 20, b = 10

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C Program to Interchange Two Numbers Using a Temporary Variable

#include <stdio.h>

int main() {
    int a, b, temp;

    // Taking input from user
    printf("Enter first number (a): ");
    scanf("%d", &a);
    printf("Enter second number (b): ");
    scanf("%d", &b);

    // Interchanging values using temp variable
    temp = a;
    a = b;
    b = temp;

    // Displaying swapped values
    printf("After interchanging:\n");
    printf("a = %d\n", a);
    printf("b = %d\n", b);

    return 0;
}

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Explanation of the Program

• int a, b, temp;: Declares three integer variables.
• User Input: Takes values for a and b using scanf.
• Swapping Logic:
  • Store value of a in temp
  • Assign value of b to a
  • Assign value of temp to b
• This ensures the values of a and b are successfully interchanged.

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Why Is Swapping Important?

• It’s a fundamental logic step in many algorithms like sorting.
• Helps build an understanding of variables, memory, and flow control.
• It’s often used in interview questions for beginners.

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Other Ways to Interchange Numbers in C

You can also swap two numbers without using a temporary variable:

a = a + b;
b = a - b;
a = a - b;

However, this method is not always recommended due to potential integer overflow issues.

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Related Topics You Might Like

• Write a C program to check even or odd

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