try yourself |run program

#include <stdio.h> 
#include <conio.h> 
void main(){ 
 int a; 
 int b; 
 int sub; 
 clrscr(); 
 printf("Enter value of a: "); 
 scanf("%d",&a); 
 printf("\n Enter value of b: "); 
 scanf("%d",&b); 
 sub = a - b; 
 printf("\n %d - %d = %d",a,b,sub); 
 getch(); 
}

Program Output

Enter value of a: 100 
Enter value of b: 20 
100 - 20 = 80