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}");
}
}
//https://pt.stackoverflow.com/q/349771/101
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