#include <stdio.h>
 
double go_pow( double base, int exp )
{
   size_t i;
   double res = 1;
 
   if ( exp < 0 )
      res = go_pow ( 1 / base , -1 * exp );
 
   for ( i = 0 ; i < (size_t) exp ; ++i )
      res *= base;
   return res;
}

int main(void){
	printf("%f\n", go_pow(2.0, -2));
	return 0;
}

Timeout