How to add two strings that are numbers? [duplicate]

Answer 1

As people allready answered this maybe another solution So you don't get errors

    private static int AddTwoStrings(string one, string two) 
    {
        int iOne = 0;
        int iTwo = 0;
        Int32.TryParse(one, out iOne);
        Int32.TryParse(two, out iTwo);
        return iOne + iTwo;
    }

Or if you want a string result.

private static String AddTwoStrings(string one, string two) 
{
    int iOne = 0;
    int iTwo = 0;
    Int32.TryParse(one, out iOne);
    Int32.TryParse(two, out iTwo);
    return (iOne + iTwo).ToString();
}

EDIT:

As Alexei Levenkov stated you could/should handle exceptions. Maybe something like this will help you during development

    private static int AddTwoStrings(string one, string two) 
    {
        int iOne = 0;
        int iTwo = 0;
        bool successParseOne = Int32.TryParse(one, out iOne);
        bool successParseTwo = Int32.TryParse(two, out iTwo);
        if (!successParseOne) 
        {
            throw new ArgumentException("one");
        }
        else if(!successParseTwo)
        {
            throw new ArgumentException("two");
        }

        return (iOne + iTwo);
    }

So when you have a wrong number you will be notified if you use try/catch

Answer 2

You will need to convert your strings to integer, add them and convert the result back to string:

int sum = 0;
foreach (string strNumber in strNumberCollection)
{
    int number;
    if (int.TryParse(strNumber, out number))
        sum += number;
}

string total = sum.ToString();

Answer 3

You need to parse the numbers from the strings:

string number1 = "309";
string number2 = "38";

int result = int.Parse(number1) + int.Parse(number2);

Then you can set the text equal to that string representation:

string addResult = result.ToString();

Note: Int32.Parse() will throw an exception if the format isn't correct. Consider using Int32.TryParse() for a bool way to capture an impossible parsing.