{{keywords>wiki library source code example reference}}
===== sqrt =====
<code c>
    double sqrt(double);
</code>

returns the square root

===== C Sourcecode Example =====
compile in linux with: gcc sqrt.c -o sqrt **-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 )
{
  printf ("square root from 4.2 is %f\n", sqrt (4.2) );
  return 0;
}
</code>

==== output ====
   output:
   user@host:~$ ./sqrt 
   square root from 4.2 is 2.049390