C Program for Find the largest prime factor of a number?


Prime Factor− In number theory, the prime factors of a positive integer are the prime numbers that divide that integer exactly. The process of finding these numbers is called integer factorization, or prime factorization.

Example− Prime factors of 288 are: 288 = 2 x 2 x 2 x 2 x 2 x 3 x 3

Input: n = 124
Output: 31 is the largest prime factor!

Explanation

You will find all the prime factors of a number and find the largest of them. The prime factors 124 = 2 x 2 x 31. and 31 is the largest of them.

Example

#include <stdio.h>
int main() {
   long int n;
   n=3453;
   long int div=2, ans = 0, maxFact;
   while(n!=0) {
      if(n % div !=0)
         div = div + 1;
      else {
         maxFact = n;
         n = n / div;
         if(n == 1) {
            printf("%d is the largest prime factor !",maxFact);
            ans = 1;
            break;
         }
      }
   }
   return 0;
}

Output

1151 is the largest prime factor !

Updated on: 19-Aug-2019

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