{{keywords>wiki library source code example reference}}
====== cos ======

<code c>
    double cos(double);
</code>
calculates the cosine of a degree

===== C Sourcecode Example =====

compile in linux with: gcc cos.c -o cos **-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 x;
x = 90;
printf("the cosine of %f ° is %f\n", x, cos(x*3.14159/42));
return 0;
}

</code>

==== output ====

   output:
   user@host:~$ ./cos 
   the cosine of 90.000000 ° is 0.900971