Convert string to integer positions

Question

    Console.Write("Digite um numero de 4 digitos: ");
    string numero = Convert.ToString(Console.ReadLine());
    int soma = 0;

    for(int i = 0; i < numero.Length; i++)
    {
        soma += Convert.ToInt32(numero[i]);
    }
    Console.WriteLine("Soma dos numeros = "+soma);

I know your put to convert the whole number (Convert.ToInt32(numero)) converts normally, but when converting only the positions, the program converts the string for HTML code, according to Unicode table, type, 2 = 50, 3 = 51, all wrong. How do I convert each value of string for int?

Answer 1

Already posted answers break the application when a value that is not a number is typed, it is correct to do this:

using static System.Console;

public class Program {
    public static void Main() {
        Write("Digite um numero de 4 digitos: ");
        var numero = ReadLine();
        var soma = 0;
        foreach (var chr in numero) {
            if (!char.IsDigit(chr)) {
                WriteLine("não é um número válido");
                return;
            }
            soma += chr - '0';
        }
        WriteLine($"Soma dos numeros = {soma}");
    }
}

Behold working in the ideone. And in the .NET Fiddle. Also put on the Github for future reference.

Answer 2

Using Linq and Generic you can do this in a simple way:

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

namespace valor_posicao_string {
    class Program {
        static void Main (string[] args) {
            Console.Write ("Digite um numero de 4 digitos: ");
            string numero = Console.ReadLine ();
            IEnumerable<int> digits = numero.Select (x => int.Parse (x.ToString ()));
            Console.WriteLine ("Soma dos numeros = " + digits.Sum());
            Console.ReadKey ();
        }
    }
}

I prevented its development by including only adaptation to the final result.

Answer 3

One string is a array of char. So when you access the numero[i] you are accessing a value of type char.

Read about char, which is nothing more than a 16-bit numeric value representing a character. To better understand what value each character represents, study the ascii table.

To get the result you expect, turn your char into string, like this:

soma += Convert.ToInt32(numero[i].ToString());