P12. Zero subset

ZeroSubset

using System;

class ZeroSubset
{
    static void Main()
    {
        int n1 = 0;
        int n2 = 0;
        int n3 = 0;
        int n4 = 0;
        int n5 = 0;
        bool noZero = true;

        Console.WriteLine("Please type 5 integer numbers: ");
        bool isValid = false;
        while (!isValid)
        {
            Console.Write("<1>: ");
            string input = Console.ReadLine();
            isValid = int.TryParse(input, out n1);
        }
        isValid = false;

        while (!isValid)
        {
            Console.Write("<2>: ");
            string input = Console.ReadLine();
            isValid = int.TryParse(input, out n2);
        }
        isValid = false;

        while (!isValid)
        {
            Console.Write("<3>: ");
            string input = Console.ReadLine();
            isValid = int.TryParse(input, out n3);
        }
        isValid = false;

        while (!isValid)
        {
            Console.Write("<4>: ");
            string input = Console.ReadLine();
            isValid = int.TryParse(input, out n4);
        }
        isValid = false;

        while (!isValid)
        {
            Console.Write("<5>: ");
            string input = Console.ReadLine();
            isValid = int.TryParse(input, out n5);
        }
        isValid = false;

        int k1;
        int k2;
        int k3;
        int k4;
        int k5;

        for (int counter = 1; counter < 32; counter++)
        {
            k1 = counter & 1;
            k2 = (counter & 3) >> 1;
            k3 = (counter & 5) >> 2;
            k4 = (counter & 9) >> 3;
            k5 = (counter & 17) >> 4;
            int sum = n1 * k1 + n2 * k2 + n3 * k3 + n4 * k4 + n5 * k5;

            if ((sum == 0) && (counter != 2) && (counter !=4) && (counter != 8) && (counter !=16))
            {
                Console.WriteLine("Zero subset:");
                if (k1 != 0) Console.Write(n1 + " ");
                if (k2 != 0) Console.Write(n2 + " ");
                if (k3 != 0) Console.Write(n3 + " ");
                if (k4 != 0) Console.Write(n4 + " ");
                if (k5 != 0) Console.Write(n5);
                Console.WriteLine();
                noZero = false;
            }
        }
        if (noZero == true) Console.WriteLine("No zero subset.");
    }
}