Find prime factors of a number
Finding prime factors of a number input by the user.
Learning Objectives
 Finding factors of number up to a level where all factors are prime.
Source Code

Run Output
Code Understanding
int n; cout<<“Enter a positive integer: “; cin>>n;
Collecting the input number from the user.
cout<<“The prime factors are: “; //Prompt before printing
for (int i=2; i <= n; i++) //Begins from 2 as no prime factor can not be less than 2
{
while(n % i == 0) //This loop works till the factor is identified
{
n /= i; //When identified the number is reduced by dividing with identified number
cout<<i<<” “; //Identified number is printed.
}
}
Notes
 This code can be modified slightly to get prime factor only once.
 One can also modified it to store primefactor in an array and then manipulate the array as required.
 Every positive integer number can be reduced to its prime factors because after reducing to prime factor further factorisation would not be possible, as a prime number is divisible by 1 and the number itself.
Suggested Filename(s): primefac.cpp
sunmitra Created: 31Jan2018  Updated: 15Sep2018