Write a Program in C to Swap Numbers Using Temporary Variable

#include <stdio.h>

int main()
{
      double firstNumber, secondNumber, temporaryVariable;

      printf("Enter first number: ");
      scanf("%lf", &firstNumber);
      printf("Enter second number: ");
      scanf("%lf",&secondNumber);
      
      // Value of firstNumber is assigned to temporaryVariable
      temporaryVariable = firstNumber;
      
      // Value of secondNumber is assigned to firstNumber
      firstNumber = secondNumber;

      // Value of temporaryVariable (which contains the initial value of firstNumber) is assigned to secondNumber
      secondNumber = temporaryVariable;

      printf("After swapping, firstNumber = %.2lf ", firstNumber);
      printf("After swapping, secondNumber = %.2lf", secondNumber);
      return 0;
}

Output

Enter first number: 1.20
Enter second number: 2.45

After swapping, firstNumber = 2.45
After swapping, secondNumber = 1.20
 

Explanation

	
  • The temporaryVariable is assigned the value of firstNumber.
  • Then, the value of firstNumber is assigned to secondNumber.
  • Finally, the temporaryVariable (which holds the initial value of firstNumber) is assigned to secondNumber which completes the swapping process.