I have a code like:

using System;
using System.Linq;
using System.Text.RegularExpressions;
                    
public class Program
{
    public static void Main()
    {
        string input = Console.ReadLine();
        var iCount = int.Parse(input);
        int vMaxQty = 4;
        
        //Sample input2 --> 1 5 4 1 1
        string input2 = Console.ReadLine();
        int val = input2.Split(' ').Sum(x=> int.Parse(x));
        int countInput2 = Regex.Matches(input2, "\\w").Count;
        
        var result = 0;
        if (countInput2 != iCount)
        {
            result = 0;
        }
        else
        {
            result = val/vMaxQty;
        }
        Console.WriteLine(result);
    }
}

My question is: How can I change the result if 1st condition (countInput2 != iCount) is true to string. Let say, result = Error!.

>Solution :

Split the string, Parse, materialize into collection, but not sum and check condition(s) instead on the collection. If check succeeds, Sum:

string input2 = Console.ReadLine();

int[] data = input2
  .Split(' ')
  .Select(item => int.Parse(item))
  .ToArray(); 

int val = -1;

// You have data array instead of string; it's easy to validate it
if (iCount == data.Length) {
  val = data.Sum();

  Console.WriteLine(val);
}
else {
  Console.WriteLine($"Invalid count: expected {iCount}, actual: {data.Length}");
}