Program statement: Two numbers are input through the keyboard into two locations C and D. write a program to interchange the contents of C and D without using temporary variable.

source file name: swap1.C 

void main()
{
int C,D;
clrscr();
printf("Interchange of two variables  program");
printf("\n enter 2 numbers C and D");
scanf("%d%d",&C,&D);
C=C+D;

D=C-D;

C=C-D;

printf("\n after interchange values are C=%d and D=%d", C,D);
getch();
}
 Output:

 1. Interchange of two variables program

enter 2 numbers C and D

100 200

after interchange values are C=200 and D=100

2.  Interchange of two variables program

enter 2 numbers C and D

25  -20

after interchange values are C= -20 and D=25