Comprehensive Guide on C Program for Swapping Two Numbers

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Swapping two numbers is a fundamental concept in programming that involves exchanging the values of two variables. This article provides an in-depth look at various C Program for Swapping Two Numbers, including real examples with different solutions and outputs. We’ll cover basic swapping with a temporary variable, swapping without a temporary variable, and swapping using bitwise XOR. Each example will be explained in detail, with structured headings and outputs for clarity.

Prerequisites

Before diving into the examples, you should be familiar with:

  • Basic syntax and structure of C programs.
  • Data types and variable declarations in C.
  • Basic input and output functions in C (such as printf and scanf).
  • Operators in C, including arithmetic and bitwise operators.

1. Swapping Using a Temporary Variable

1.1 Explanation

The most common and straightforward method to swap two numbers is by using a temporary variable. This method is easy to understand and implement.

1.2 Program: Swapping Using a Temporary Variable

C
#include <stdio.h>

int main() {
    int a, b, temp;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);

    printf("Before swapping: a = %d, b = %d\n", a, b);

    temp = a;
    a = b;
    b = temp;

    printf("After swapping: a = %d, b = %d\n", a, b);

    return 0;
}

1.3 Output

C
Enter two numbers: 5 10
Before swapping: a = 5, b = 10
After swapping: a = 10, b = 5

2. Swapping Without Using a Temporary Variable

2.1 Explanation

Swapping two numbers without using a temporary variable can be done using arithmetic operations. This method utilizes the properties of addition and subtraction.

2.2 Program: Swapping Without Using a Temporary Variable

C
#include <stdio.h>

int main() {
    int a, b;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);

    printf("Before swapping: a = %d, b = %d\n", a, b);

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

    printf("After swapping: a = %d, b = %d\n", a, b);

    return 0;
}

2.3 Output

C
Enter two numbers: 5 10
Before swapping: a = 5, b = 10
After swapping: a = 10, b = 5

3. Swapping Using Bitwise XOR

3.1 Explanation

The XOR bitwise operation can also be used to swap two numbers without a temporary variable. This method is less common but is a neat trick often asked in technical interviews.

3.2 Program: Swapping Using Bitwise XOR

C
#include <stdio.h>

int main() {
    int a, b;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);

    printf("Before swapping: a = %d, b = %d\n", a, b);

    a = a ^ b;
    b = a ^ b;
    a = a ^ b;

    printf("After swapping: a = %d, b = %d\n", a, b);

    return 0;
}

3.3 Output

C
Enter two numbers: 5 10
Before swapping: a = 5, b = 10
After swapping: a = 10, b = 5

4. Swapping Using Pointers

4.1 Explanation

Swapping using pointers involves passing the addresses of the variables to a function and swapping their values using dereferencing.

4.2 Program: Swapping Using Pointers

C
#include <stdio.h>

void swap(int *x, int *y) {
    int temp;
    temp = *x;
    *x = *y;
    *y = temp;
}

int main() {
    int a, b;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);

    printf("Before swapping: a = %d, b = %d\n", a, b);

    swap(&a, &b);

    printf("After swapping: a = %d, b = %d\n", a, b);

    return 0;
}

4.3 Output

C
Enter two numbers: 5 10
Before swapping: a = 5, b = 10
After swapping: a = 10, b = 5

5. Swapping Using Macros

5.1 Explanation

Using macros in C, we can define a swap operation that can be reused throughout the code.

5.2 Program: Swapping Using Macros

C
#include <stdio.h>

#define SWAP(a, b) { int temp = a; a = b; b = temp; }

int main() {
    int a, b;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);

    printf("Before swapping: a = %d, b = %d\n", a, b);

    SWAP(a, b);

    printf("After swapping: a = %d, b = %d\n", a, b);

    return 0;
}

5.3 Output

C
Enter two numbers: 5 10
Before swapping: a = 5, b = 10
After swapping: a = 10, b = 5

Conclusion

This article covered various C Program for Swapping Two Numbers, including using a temporary variable, without a temporary variable, using bitwise XOR, using pointers, and using macros. Each method has its unique way of achieving the swap, providing multiple approaches depending on the scenario and requirements. By understanding these methods, you can choose the most appropriate one for your specific needs in C programming.