C# Returning Wrong Integer Value

Question

i am trying to return an index based on the input of an user, the input is 2 characters only, like, a1, b2, c3...

public int returnInt(string x)
        {
            if (x == "a")
                return 0;
            else if (x == "b")
                return 1;
            else if (x == "c")
                return 2;
            else if (x == "d")
                return 3;
            else if (x == "e")
                return 4;
            else if (x == "f")
                return 5;
            else if (x == "g")
                return 6;
            else if (x == "h")
                return 7;
            else if (x == "1")
                return 0;
            else if (x == "2")
                return 1;
            else if (x == "3")
                return 2;
            else if (x == "4")
                return 3;
            else if (x == "5")
                return 4;
            else if (x == "6")
                return 5;
            else if (x == "7")
                return 6;
            else if (x == "8")
                return 7;
            return 0;
        }

And this is where i use the method:

var toMove = myButtonArray[returnInt(totxt.Text.Substring(0)), returnInt(totxt.Text.Substring(1))];

the method works fine for the second substring, but it doesn't work for the first substring(0). Can anyone help me about this? When I type a1, program should return to 1 and 1 but it only returns 0 for the first substring.

Answer 1

Let's operate with single characters, not strings:

public int returnInt(char x) =>
    x >= 'a' && x <= 'h' ? x - 'a'
  : x >= '1' && x <= '8' ? x - '1'
  : 0;

Then you can put:

var toMove = myButtonArray[returnInt(totxt.Text[0]), returnInt(totxt.Text[1])];

please, note, that we get 0th and 1st char, not string