01: // predefined function fabs()
02: #include<stdio.h>
03: #include<stdlib.h>
04: #include<math.h>
05: 
06: int main(int argc, char **argv){
07: 
08:   double a, b;
09:   printf("Please enter two numbers: ");
10:   scanf("%lg%lg", &a, &b);
11: 
12:   printf("The absolute difference between %g and %g is %g\n", a, b, fabs(a-b)); // despite the name is double fabs(double x);
13:   return 0;
14: }
15: 
16: