How to read an integer using console.readline()?

Question

I'm a beginner who is learning .NET.

I tried parsing my integer in console readline but it shows a format exception.

My code:

using System;
namespace inputoutput
{
    class Program
    {        
        static void Main()
        {
            string firstname;
            string lastname;
         // int age = int.Parse(Console.ReadLine());
            int age = Convert.ToInt32(Console.ReadLine());
            firstname = Console.ReadLine();
            lastname=Console.ReadLine();
            Console.WriteLine("hello your firstname is {0} Your lastname is {1} Age: {2}",
                firstname, lastname, age);
        }
    }
}

This code works for me. Are you sure you are entering a valid integer for the first line? Perhaps you could put the readline into a string variable first and check the value before you parse it? — Chris, Nov 25 '17 at 12:10
Possible duplicate: https://stackoverflow.com/questions/24443827/reading-an-integer-from-user-input — cSteusloff, Nov 25 '17 at 12:17
yes.It worked for me.i gave valid integer.Thanks a lot - Grant Winney — Helen Anita, Nov 25 '17 at 12:17

score 3 · Accepted Answer · answered Nov 25 '17 at 12:11

If it's throwing a format exception then that means the input isn't able to be parsed as an int. You can check for this more effectively with something like int.TryParse(). For example:

int age = 0;
string ageInput = Console.ReadLine();
if (!int.TryParse(ageInput, out age))
{
    // Parsing failed, handle the error however you like
}
// If parsing failed, age will still be 0 here.
// If it succeeded, age will be the expected int value.

score 0 · Answer 2 · answered Nov 25 '17 at 12:11

0

Your code is absolutely correct but your input may not be integer so you are getting the errors. Try to use the conversion code in try catch block or use int.TryParse instead.

answered Nov 25 '17 at 12:11

AjayR

4,169
4
44
78

TryPars is better, less overhead – Sybren Nov 25 '17 at 15:21

score 0 · Answer 3 · answered Nov 25 '17 at 12:13

You can handle invalid formats except integer like this;

        int age;
        string ageStr = Console.ReadLine();
        if (!int.TryParse(ageStr, out age))
        {
            Console.WriteLine("Please enter valid input for age ! ");
            return;
        }

cSteusloff · Answer 4 · 2017-11-25T12:15:31.803

-1

You can convert numeric input string to integer (your code is correct):

int age = Convert.ToInt32(Console.ReadLine());

If you would handle text input try this:

int.TryParse(Console.ReadLine(), out var age);

edited Nov 25 '17 at 12:15

answered Nov 25 '17 at 12:11

cSteusloff

2,487
7
30
51

1

That is literally the code from the question. How does it answer the question? – UnholySheep Nov 25 '17 at 12:11

How to read an integer using console.readline()?

4 Answers4

Linked

Related