Programming Forums > Application Development > C#

357mag · Jul 29th, 2007, 1:07 PM

I've got this program that inputs an integer and then outputs the prime factorization. Here is the code:

using System;

public class WhileLoop
{
    public static void Main()
    {
        int number;

        Console.Write("Enter an integer: ");
        number = Convert.ToInt32(Console.ReadLine());

        for (int i = 2; i <= number;)
        {
            if (number % i == 0)
            {
                Console.Write(i + " * ");
                number = number / i;
            }

            else
                i++;
        }

        Console.WriteLine();
    }
}

I want the program to not only output the prime numbers, but I want to show the multiplication symbol between the numbers. But the problem is that I end up with one too many symbols. I've deduced that I need one less multiplication symbol than I have digits. So if there are 7 digits output, all I need is 6 symbols. If there are 4 digits output, all I need is 3 symbols. I want the output to look like this, say for the factorization of 20:

2 * 2 * 5

And like this for the factorization of 150:

2 * 3 * 5 * 5

I don't know how to do it though.

Booooze · Jul 29th, 2007, 1:14 PM

Well, if you stored it in a string, you could just chop off the last * symbol. Or I think you could just throw another if statement in there within the loop and current if statement. Have it check to see if you on the last loop , if so, write i instead of i + *. Will that work?

357mag · Jul 29th, 2007, 1:53 PM

I'd need to see some specific code. I don't know what to write.

357mag · Jul 29th, 2007, 2:17 PM

Wait. I think I got it figured out and it appears to be working. I did this:

(Toggle Plain Text)

if (number % i == 0)
{
    if (i == number)
       Console.Write(i);

    else
       Console.Write(i + " * ");
        number = number / i;
}

Jul 29th, 2007, 1:07 PM	#1
357mag Hobbyist Programmer Join Date: Mar 2005 Posts: 148 Rep Power: 4	One more thing I'd like to do I've got this program that inputs an integer and then outputs the prime factorization. Here is the code: (Toggle Plain Text) using System; public class WhileLoop { public static void Main() { int number; Console.Write("Enter an integer: "); number = Convert.ToInt32(Console.ReadLine()); for (int i = 2; i <= number;) { if (number % i == 0) { Console.Write(i + " * "); number = number / i; } else i++; } Console.WriteLine(); } } using System; public class WhileLoop { public static void Main() { int number; Console.Write("Enter an integer: "); number = Convert.ToInt32(Console.ReadLine()); for (int i = 2; i <= number;) { if (number % i == 0) { Console.Write(i + " * "); number = number / i; } else i++; } Console.WriteLine(); } } I want the program to not only output the prime numbers, but I want to show the multiplication symbol between the numbers. But the problem is that I end up with one too many symbols. I've deduced that I need one less multiplication symbol than I have digits. So if there are 7 digits output, all I need is 6 symbols. If there are 4 digits output, all I need is 3 symbols. I want the output to look like this, say for the factorization of 20: 2 * 2 * 5 And like this for the factorization of 150: 2 * 3 * 5 * 5 I don't know how to do it though.

Jul 29th, 2007, 2:17 PM	#4
357mag Hobbyist Programmer Join Date: Mar 2005 Posts: 148 Rep Power: 4	Wait. I think I got it figured out and it appears to be working. I did this: (Toggle Plain Text) if (number % i == 0) { if (i == number) Console.Write(i); else Console.Write(i + " * "); number = number / i; } if (number % i == 0) { if (i == number) Console.Write(i); else Console.Write(i + " * "); number = number / i; } Last edited by 357mag; Jul 29th, 2007 at 2:19 PM. Reason: mistake

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Jul 29th, 2007, 1:14 PM	#2
Booooze Expert Programmer Join Date: Mar 2006 Location: Igloo Posts: 710 Rep Power: 3	Well, if you stored it in a string, you could just chop off the last * symbol. Or I think you could just throw another if statement in there within the loop and current if statement. Have it check to see if you on the last loop , if so, write i instead of i + *. Will that work?

Jul 29th, 2007, 1:53 PM	#3
357mag Hobbyist Programmer Join Date: Mar 2005 Posts: 148 Rep Power: 4	I'd need to see some specific code. I don't know what to write.

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Programming Forums > Application Development > C#

One more thing I'd like to do