1 double floor (      double x );
2 float floor (       float x );
3 long double floor ( long double x );

 1 #include <stdio.h>
 2 #include <math.h>
 3 
 4 int main ()
 5 {
 6   printf ("floor of 2.3 is %.1lf/n", floor (2.3) );
 7   printf ("floor of 2.6 is %.1lf/n", floor (2.6) );
 8   printf ("floor of -2.3 is %.1lf/n", floor (-2.3) );
 9   printf ("floor of -2.6 is %.1lf/n", floor (-2.6) );
10   return 0;
11 }