fork(2) download
copy 
  1. #include <stdio.h>
  2.  
  3. // Optimized recursive solution to calculate pow(x, n)
  4. // using divide and conquer
  5. int power(int x, unsigned n)
  6. {
  7.     // base condition
  8.     if (n == 0)
  9.         return 1;
  10.  
  11.     // calculate sub-problem recursively
  12.     int pow = power(x, n / 2);
  13.  
  14.     if (n & 1) // if y is odd
  15.         return x * pow * pow;
  16.  
  17.     // else y is even
  18.     return pow * pow;
  19. }
  20.  
  21. // main function
  22. int main(void)
  23. {
  24.     int x = -2;
  25.     unsigned n = 10;
  26.  
  27.     printf("pow(%d,%d) = %d", x, n, power(x, n));
  28.  
  29.     return 0;
  30. }
Success #stdin #stdout 0s 4548KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
pow(-2,10) = 1024
https://ideone.com/it8v4m
Efficiently implement power function
language:
C (gcc 8.3)
created:
6 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!