Question

C#

please answer if you know, don't copy others answers,

Prime factors are the combination of the smallest prime numbers, that, when multiplied together, will produce the original number. Consider the following example:

Prime factors of 4 are: 2 x 2

Prime factors of 7 are: 7

Prime factors of 30 are: 2 x 3 x 5

Prime factors of 40 are: 2 x 2 x 2 x 5

Prime factors of 50 are: 2 x 5 x 5

Create a console application with a method named PrimeFactors that, when passed an int variable as a parameter, returns a string showing its prime factors.

Use the debugging tools and write unit tests to ensure that your function works correctly with multiple inputs and returns the correct output.

Answer 1

Program:

using System;
class HelloWorld {
    
    public static void PrimeFactors(int num) {
        Console.Write($"Prime Factors of {num} are:  ");

        // for even numbers
        while (num % 2 == 0)
        {
            Console.Write("2 ");
            num /= 2;
        }
        
        // if n is an odd number
        for(int i = 3; i <= Math.Sqrt(num); i += 2)
        {
            while (num % i == 0)
            {
                Console.Write($"{i} ");
                num /= i;
            }
        }

        // If n is greater than 2 and Prime number
        if (num > 2)
        {
            Console.Write($"{num} ");
        }
    }
  static void Main() {
    Console.Write("Enter a number greater than 1: ");
    if (int.TryParse(Console.ReadLine(), out int num) && num > 1)
    {
        PrimeFactors(num);
    }
    else
    {
        Console.WriteLine("Invalid input!!");
    }
  }
}

Output: