# Find largest prime factor of a number using C++.

C++Server Side ProgrammingProgramming

Consider we have an element x, we have to find the largest prime factor of x. If the value of x is 6,  then-largest prime factor is 3. To solve this problem, we will just factorize the number by dividing it with the divisor of a number and keep track of the maximum prime factor.

## Example

Live Demo

#include <iostream>
#include<cmath>
using namespace std;
long long getMaxPrimefactor(long long n) {
long long maxPF = -1;
while (n % 2 == 0) {
maxPF = 2;
n /= 2;
}
for (int i = 3; i <= sqrt(n); i += 2) {
while (n % i == 0) {
maxPF = i;
n = n / i;
}
}
if (n > 2)
maxPF = n;
return maxPF;
}
int main() {
long long n = 162378;
cout << "Max Prime factor of " << n << " is " << getMaxPrimefactor(n);
}

## Output

Max Prime factor of 162378 is 97
Published on 30-Oct-2019 05:53:55