5 Ways to Swap Numbers In C Programming

There are various methods to swap two numbers. Here we are going to discuss some of the methods.

• Swapping of two numbers using a third/temp variable.
• Swapping of two numbers without using third/temp variable.
• Swapping of two numbers using bit-wise XOR operator.
• Swapping of two numbers using pointer.
• Swapping of two numbers using function.

1. Swapping of two numbers using a third/temp variable.

To swap two numbers using the third variable we have to declare a temp variable.

temp=x; //contains of x will be assigned to temp

Again y value we will assign to x .x value will be replaced with the y value.

x=y;

Now temp value we will assign to y.

y=temp;

Program :

#include<stdio.h>
int main() {
  double first, second, temp;
  printf("Enter first number: ");
  scanf("%lf", &first);
  printf("Enter second number: ");
  scanf("%lf", &second);

  // value of first is assigned to temp
  temp = first;

  // value of second is assigned to first
  first = second;

  // value of temp (initial value of first) is assigned to second
  second = temp;

  // %.2lf displays number up to 2 decimal points
  printf("\nAfter swapping, first number = %.2lf\n", first);
  printf("After swapping, second number = %.2lf", second);
  return 0;
}

2. Swapping of two numbers without using a third/temp variable.

Swapping can be done also without using a third variable.

x=x+y;//This will modify x=30 & y=20

y=x-y;//This will modify y value i.e y=10 & x=30

x=x-y;//This will modify x value i.e x=20 & y=10

Program :

#include <stdio.h>
int main()
{
int a, b;
printf("Enter the first number: ");
scanf("%d", &a);
printf("Enter the second number: ");
scanf("%d", &b);
a = a - b;
b = a + b;
a = b - a;
printf("After swapping, a = %d\n", a);
printf("After swapping, b = %d\n", b);
return 0;
}

3 .Swapping of two numbers using bit-wise XOR operator

Program :

#include <stdio.h>
int main()
{
int num1, num2;
printf("\nEnter First Number : ");
scanf("%d", &num1);
printf("\nEnter Second Number : ");
scanf("%d", &num2);
num1 = num1 ^ num2;
num2 = num1 ^ num2;
num1 = num1 ^ num2;
printf("\n Numbers after Exchange : ");
printf("\n Num1 = %d\n and\n Num2 = %d\n", num1, num2);
return (0);
}

4 . Swapping of two numbers using a pointer.

#include <stdio.h>
int main()
int x, y, *a, *b, temp;
printf("Enter the value of x and y\n");
scanf("%d%d", &x, &y);
printf("Before Swapping\nx = %d\ny = %d\n", x, y);
a = &x;
b = &y;
temp = *b;
*b = *a;
*a = temp;
printf("After Swapping\nx = %d\ny = %d\n", x, y);
return 0;
}

5 . Swapping of two numbers using function

#include <stdio.h>
void swap(int, int);
int main()
{
int a, b;
printf("Enter values for a and b\n");
scanf("%d%d", &a, &b);
printf("\n\nBefore swapping: a = %d and b = %d\n", a, b);
swap(a, b);
return 0;
}
void swap(int x, int y)
{
int temp;
temp = x;
x = y;
y = temp;
printf("\nAfter swapping: a = %d and b = %d\n", x, y);
}