C Program to Swap two Numbers
Swapping two numbers means exchanging their values. In this article, we will learn how to swap two numbers in the C programming language.
Swap Two Numbers Using a Temporary Variable
Below is the C program to swap two numbers using a temporary variable.
C
#include <stdio.h>
int main()
{
int x, y;
printf ( "Enter Value of x " );
scanf ( "%d" , &x);
printf ( "\nEnter Value of y " );
scanf ( "%d" , &y);
int temp = x;
x = y;
y = temp;
printf ( "\nAfter Swapping: x = %d, y = %d" , x, y);
return 0;
}
|
Output
Enter Value of x
Enter Value of y
After Swapping: x = 0, y = 0
Complexity Analysis
- Time Complexity: O(1)
- Auxiliary Space: O(1)
Explanation
We swap two numbers by storing the value of one number in a temporary variable, assigning the value of the second number to the first number, and then assigning the value stored in the temporary variable to the second number.
Swap Two Numbers Without Using a Temporary Variable
Below is the C/C++ program to swap two numbers without using a temporary variable.
C
#include <stdio.h>
int main()
{
int a, b;
printf ( "Enter the two numbers : \n" );
scanf ( "%d %d" , &a, &b);
printf ( "Before swapping A is : %d and B is %d \n" , a,
b);
a = a + b;
b = a - b;
a = a - b;
printf ( "After swapping A is : %d and B is : %d \n" , a,
b);
return 0;
}
|
Output
Enter the two numbers :
Before swapping A is : 0 and B is 32767
After swapping A is : 32767 and B is : 0
Complexity Analysis
- Time Complexity: O(1)
- Auxiliary Space: O(1)
Explanation
The idea is to use arithmetic operators. We will take the sum of the two numbers and store it in one number and store the difference of both numbers in the other number. Finally, we will store the difference of both numbers in the first number. Since the values will be updated after the first two operations we will be able to swap the numbers.
Refer to the complete article on How to swap without using a temporary variable? for more details!
Last Updated :
18 Jul, 2023
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