**C program to display prime factors of a number**

Factors of a number that are prime numbers are called Prime factors of that number. For example: 2 and 5 are the prime factors of 10.

**Logic to check prime factors of a number**

Step by step descriptive logic to find prime factors.

- Input a number from the user. Store it in some variable say num.
- Run a loop from 2 to num/2, increment 1 in each iteration. The loop structure should look like for(i=2; i<=num/2; i++).

You may think why loop from 2 to num/2? Because the prime number starts from 2 and any factor of a number n is always less than n/2.

- Inside the loop, first check if iis a factor of num or not. If it is a factor then check it is prime or not.

Print the value of i if it is prime and a factor of num.

/** * C program to find all prime factors of a given number */ #include <stdio.h> #include<conio.h> Void main() { int i, j, num, isPrime; /* Input a number from user */ printf("\n\t\t\t...Welcome To EduNews.Tech... "); printf("Enter any number to print Prime factors: "); scanf("%d", &num); printf("All Prime Factors of %d are: \n", num); /* Find all Prime factors */ for(i=2; i<=num; i++) { /* Check 'i' for factor of num */ if(num%i==0) { /* Check 'i' for Prime */ isPrime = 1; for(j=2; j<=i/2; j++) { if(i%j==0) { isPrime = 0; break; } } /* If 'i' is Prime number and factor of num */ if(isPrime==1) { printf("%d, ", i); } } } printf("\n\n\n\t\t\tThankyou for Joining Us !"); printf("\n\t\t\t!Regards EduNews !"); getch(); }

**Program Output:**

I hope this post helps you to understand the “Prime factors of a number” and its implementation in C programming language.

Keep coding 🙂