{{keywords>wiki library source code example reference}}
===== floor =====
<code c>
    double floor(double);
</code>
rounding down a number

===== C Sourcecode Example =====
compile in linux with: gcc floor.c -o floor **-lm** -Wall
<code c>     
#include <stdio.h> /* including standard library */
//#include <windows.h> /* uncomment this for Windows */

#include <math.h> /* including math library */

int main ( void ) 
{
double y,x;
x = 4.2;
y = 9.9;
printf("floor of %f is %f\n", x, floor(x) );
printf("floor of %f is %f\n ",y , floor(y) );
return 0;
}

</code>

==== output ====
   output:
   user@host:~$ ./floor 
   floor of 4.200000 is 4.000000
   floor of 9.900000 is 9.000000