pow_function.c

#include <stdio.h>
//http://stackoverflow.com/questions/101439/the-most-efficient-way-to-implement-an-integer-based-power-function-powint-int

/*          
   all exponential values (e.g.5)  was chaged to 2 system 
   
                      * check even or odd
   <----------------------->
      2^3  2^2  2^1  2^0
   0b  1    0    1    0 : 10 
   0b  0    1    0    1 : 05 
   <----------------------->
          
   base *= base  :  2 ^ x 
*/


int ipow(int base, int exp)
{
    int result = 1;
    while (exp)
    {
        if (exp & 1) // exp is even 
            result *= base;
  
        exp >>= 1;
        base *= base;  // 2 ^ x 
    }

    return result;
}

int main(void) {
	
  int ret;
  
  ret = ipow(5,5);
  printf("5 5 %d \n",ret);
	
  ret = ipow(5,10);
  printf("5 10 %d \n",ret);	
	
  return 0;
}