{"id":25535,"date":"2017-05-30T18:59:26","date_gmt":"2017-05-30T13:29:26","guid":{"rendered":"https:\/\/www.wikitechy.com\/technology\/?p=25535"},"modified":"2017-05-30T18:59:26","modified_gmt":"2017-05-30T13:29:26","slug":"write-a-program-to-calculate-pow-xn","status":"publish","type":"post","link":"https:\/\/www.wikitechy.com\/technology\/write-a-program-to-calculate-pow-xn\/","title":{"rendered":"Write a program to calculate pow (x,n)"},"content":{"rendered":"

Below solution divides the problem into subproblems of size y\/2 and call the subproblems recursively<\/a>.<\/strong><\/p>\n[ad type=”banner”]\n

<\/div> 
#include<stdio.h> \/* Function to calculate x raised to the power y *\/int power(int x, unsigned int y){    if (y == 0)        return 1;    else if (y%2 == 0)        return power(x, y\/2)*power(x, y\/2);    else        return x*power(x, y\/2)*power(x, y\/2);} \/* Program to test function power *\/int main(){    int x = 2;    unsigned int y = 3;     printf("%d", power(x, y));    return 0;}<\/code><\/pre> <\/div>\n
Time Complexity: <\/strong>O(n)
\nSpace Complexity:<\/strong> O(1)
\nAlgorithmic Paradigm: <\/strong>Divide and conquer.<\/p>\n
Above function can be optimized to O(logn) by calculating power(x, y\/2) only once and storing it.<\/p>\n
 
 <\/div> 
\/* Function to calculate x raised to the power y in O(logn)*\/int power(int x, unsigned int y){    int temp;    if( y == 0)        return 1;    temp = power(x, y\/2);    if (y%2 == 0)        return temp*temp;    else        return x*temp*temp;}<\/code><\/pre> <\/div>\n
Time Complexity of optimized solution:<\/strong> O(logn)
\nLet us extend the pow function to work for negative y and float x.<\/p>\n[ad type=”banner”]\n
 
 <\/div> 
\/* Extended version of power function that can work for float x and negative y*\/#include<stdio.h> float power(float x, int y){    float temp;    if( y == 0)       return 1;    temp = power(x, y\/2);           if (y%2 == 0)        return temp*temp;    else    {        if(y > 0)            return x*temp*temp;        else            return (temp*temp)\/x;    }}   \/* Program to test function power *\/int main(){    float x = 2;    int y = -3;    printf("%f", power(x, y));    return 0;}<\/code><\/pre> <\/div>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
Write a program to calculate pow(x,n) – Divide and Conquer – Above function can be optimized to O(logn) by calculating power(x, y\/2) only once and storing it.<\/p>\n","protected":false},"author":1,"featured_media":26073,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73719],"tags":[73765,73766,73773,73778,73780,73776,73768,73767,73770,73771,73772,73769,73774,73779,73777,73764],"class_list":["post-25535","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-divide-and-conquer","tag-c-program-to-calculate-power-of-a-number","tag-c-program-to-calculate-power-of-a-number-using-recursion","tag-c-program-to-find-power-of-a-number-using-for-loop","tag-c-program-to-find-power-of-a-number-using-function","tag-c-program-to-find-power-of-a-number-without-using-pow-function","tag-c-programming-power-function","tag-calculate-power-of-a-number","tag-how-to-calculate-power","tag-how-to-calculate-power-in-c","tag-how-to-calculate-power-number","tag-how-to-calculate-power-of-2","tag-how-to-calculate-power-of-a-number","tag-implement-powx","tag-implement-power-function-leetcode","tag-implement-power-function-using-binary-search","tag-write-a-program-to-calculate-powx"],"_links":{"self":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/25535","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/comments?post=25535"}],"version-history":[{"count":0,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/25535\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/media\/26073"}],"wp:attachment":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/media?parent=25535"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/categories?post=25535"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/tags?post=25535"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}