Converting string to sum C#

Question

So this time, I've got numbers entered in as a list, with a space delimiting each number. The code I've written now places the number in a row as it should, but fails out when I try and convert the string to Int32, killing the program and not giving me the sum. I don't understand errors well enough yet to be able to decipher exactly what the error is. How does a guy convert split string arrays into numbers to produce a sum?

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

    namespace Dynamic_Entry
    {
    class Program
     {
    static void Main()
    {
        Console.Write("Please provide a list of numbers, separated by spaces: ");
        string list = Console.ReadLine();
        string[] parts = list.Split(' ');
        int sum = 0;

        for (int i = 0; i < parts.Length ; i++)
        {
            Console.WriteLine("{0, 5}", parts[i]);

        }

        sum = Convert.ToInt32(list);
        Console.WriteLine("-----");
        Console.Write("{0, 5}", sum);
        Console.ReadLine();

        }
      }
    }

xanatos · Accepted Answer · 2013-08-02 07:31:11Z

5

for (int i = 0; i < parts.Length; i++)
{
    Console.WriteLine("{0, 5}", parts[i]);
    sum += Convert.ToInt32(parts[i]);
}

Fixed.

You were trying to convert "1 2 3 4 5 55" to an int. You must convert "1", "2, "3"... to an int and add them to sum.

I'll add that if you want to Split the string, it would be better to do something like

string[] parts = list.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

In this way multiple spaces between numbers are removed (1 2 3 for example)

Andrei had posted a very simple example of use of LINQ...

int sum = parts.Sum(p => Convert.ToInt32(p));

This you would put OUTSIDE the for cycle. It converts to int and adds all the "parts". It means "for each part convert it to int and add it. Return the sum".

edited Aug 2, 2013 at 7:31

answered Aug 2, 2013 at 7:22

xanatos

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4 Comments

user1707042 Over a year ago

Wow! Thanks for the quick response. However, can you explain how sum makes it out of the for loop? I thought the for loop was kinda like Vegas...you know, what happens in the loop, stays in the loop. How is the program able to grab the sum out of the loop when the loop completes?

Panagiotis Kanavos Over a year ago

sum is defined outside the loop

Bimal Das Over a year ago

int sum = parts.Sum(p => Convert.ToInt32(p)); This will give wrong result since "p" will be a "char" data type.

xanatos Over a year ago

@BimalDas ???? parts is string[] because it is the result of a string.Split

Panagiotis Kanavos · Accepted Answer · 2013-08-02 07:34:22Z

2

You can convert each string to an int and add them in a loop as @xanatos proposes, or you can use LINQ and Enumerable.Sum(), eg:

var sum=parts.Sum(part=>Convert.ToInt32(part));

or

var sum=parts.Select(part=>Convert.ToInt32(part))
     .Sum();

The real benefit comes when you have more complex expressions, eg. when you need to filter values, extract properties etc.

For example, you could filter values greater than 3 like this:

var sum=parts.Select(part=>Convert.ToInt32(part))
     .Where(num=>num>3)
     .Sum();

answered Aug 2, 2013 at 7:34

Panagiotis Kanavos

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