Question

I’m not sure how else I can get a loop going that checks to find the letter, checks if it’s capital or not by adding a ‘C’ (or not), and continues with the rest of the characters in the string. I’m not very good at explaining what’s happening here as I’m sort of new with C#. But ‘i’ in the ‘for’ loop never gets reset back to 0, making it so that you receive the wrong output.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Encrypt
{
    class Program
    {
        static char[] alphabet = new char[52] { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'z' };
        static void Main(string[] args)
        {

            string input = Console.ReadLine();
            string output = Decode(input);
            Console.WriteLine(output);
            Console.ReadLine();

        }

        static string Decode(string input)
        {
            string output = "";
            foreach (Char c in input)
            {
                for (int i = 0; i < alphabet.GetLength(0); i++)
                {
                    if (c == alphabet[i])
                    {
                        int intoutput = i + 1;
                        if (intoutput > 26)
                        {
                            intoutput = intoutput - 26;
                            output = "C" + intoutput + " ";
                        }
                        else
                        {
                            output = intoutput + " ";
                        }
                    }
                }
            }
        return output;
        } 
    }
}

Answer 1

Your issue isn’t with resetting i, your issue is with

output = "C" + intoutput + " ";
...
output = intoutput + " ";

These do not append to output, they assign to output, meaning the previously assigned value gets lost. You’ll want something like

output = output + "C" + intoutput + " ";
...
output = output + intoutput + " ";