CODEWITHSUNDEEP
c#
Comp
Comp

Reputation: 134

Can't convert from int to char error c#

I have this exercise. I don't know what the problem is, but I keep getting the error - can someone help me what is wrong please?

Unhandled Exception: System.InvalidCastException: Unable to cast object of type 'System.String[]' to type 'System.IConvertible'.
at System.Convert.ToInt32(Object value)
at exercise_4.Program.Main(String[] args) in D:\Courses\c#\beginner\visual studio\section 6 exercises\exercise 4\exercise 4\Program.cs:line 20

This is what is written in my console

Write a program and ask the user to supply a list of comma separated numbers (e.g 5, 1, 9, 2, 10). If the list is empty or includes less than 5 numbers, display "Invalid List" and ask the user to re-try; otherwise, display the 3 smallest numbers in the list. 

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

namespace exercise_4
{
  class Program
  {
    static void Main(string[] args)
    {
      while (true)
      {
        Console.WriteLine("write numbers seperated with coma");
        var numbers = new List<int>();
        var input = (Console.ReadLine());
        var value = input.Split(',');
        var conv =Convert.ToInt32(value);
        numbers.Add(conv);

        if (value.Length < 5)
        {
          Console.WriteLine("invalid list!! retry");
          continue;
        }
        else
        {
          numbers.Sort();
          Console.WriteLine(numbers[0] , numbers[1], numbers [2]);
        }
      }
    }
  }
}

Thanks for answers.

Upvotes: 1

Views: 2636

Answers (2)

Mehdi Isaloo
Mehdi Isaloo

Reputation: 183

You can replace this:

var values = input.Split(',');

to this:

var values = input.Split(',').Select(a => int.Parse(a)).OrderBy(a => a).Take(3);

It'll give you three smallest numbers.

Upvotes: 2

ashin
ashin

Reputation: 2613

Split method returns an array of strings. The exception is thrown because the following statement tries to cast the string[] to int:

 var conv =Convert.ToInt32(value);

You should iterate and parse each item in the array as follows:

while (true)
        {
            Console.WriteLine("write numbers seperated with coma");
            List<int> numbers = new List<int>();
            var input = (Console.ReadLine());
            var values = input.Split(',');

            foreach (var value in values)
            {
                int number;

                // If the input can be parsed to int, add it to numbers list.
                if (int.TryParse(value, out number))
                {
                    numbers.Add(number);
                }
            }

            if (numbers.Count < 5)
            {
                Console.WriteLine("invalid list!! retry");
                continue;
            }
            else
            {
                numbers.Sort();
                numbers.Take(3)
                       .ToList()
                       .ForEach(number => Console.WriteLine(number));
            }
        }

Upvotes: 2

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