01: // predefined function abs()
02: #include<stdio.h>
03: #include<stdlib.h>
04: 
05: int main(int argc, char **argv){
06: 
07:   double a, b;
08:   printf("Please enter two numbers: ");
09:   scanf("%lg%lg", &a, &b);
10: 
11:   printf("The absolute difference between %g and %g is %g\n", a, b, abs(a-b)); // why we have a compile warning?
12:   return 0;
13: }
14: 
15: