#include <stdio.h>
#include <math.h>        // Must include math.h header.

// To compile:
//    gcc math.c -lm

int main ()
{
  double x = 1.5;
  double y = 2.0;

  printf ("x = %lf   ceil(x) = %lf\n", x, ceil(x) );            // 2.0
  printf ("x = %lf   floor(x) = %lf\n", x, floor(x) );          // 1.0 
  printf ("x = %lf   sqrt(x) = %lf\n", x, sqrt(x) );            // 1.224
  printf ("x = %lf   exp(x) = %lf\n", x, exp(x) );              // 4.481
  printf ("x = %lf   log(x) = %lf\n", x, log(x) );              // 0.405

  x = -1.5;
  printf ("x = %lf   fabs(x) = %lf\n", x, fabs(x) );            // 1.5
  printf ("x = %lf  y = %lf   x^y = %lf\n", x, y, pow(x,y) );   // 2.25
}