break Console.WriteLine finally int.Parse String Length while

`Console.ReadLine`

This method reads input from the console—when the user presses enter, it returns a string. We can process this string like any other in a C# program.

C# programs will often use the Console.ReadLine method in a loop. With ReadLine() method calls we can repeatedly prompt for input.

Example

When developing programs, we will often want to loop through user inputs. This example uses a while-true loop and the Console.ReadLine() method.

Part 1 With a while-true loop the code loops infinitely. The loop will only exit with a special "exit" command.

Part 2 We print a prompt and then read in a line from the console by calling Console.ReadLine.

Part 3 We check the string returned, and if it equals "exit," the program terminates. We show the length for each string typed.

using System;

class Program
{
    static void Main()
    {
        // Part 1: loop indefinitely.
        while (true)
        {
            // Part 2: get user input with a prompt.
            Console.WriteLine("Enter input:");
            string line = Console.ReadLine();

            // Part 3: check string and report output.
            if (line == "exit")
            {
                break;
            }
            Console.Write("You typed ");
            Console.Write(line.Length);
            Console.WriteLine(" character(s)");
        }
    }
}Enter input:
Dot
You typed 3 character(s)
Enter input:
Net Perls
You typed 9 character(s)
Enter input:

Integer input

Here we use the string from Console.ReadLine as an integer value. We can invoke the int.TryParse method to see if the result string is an integer representation.

Step 1 The line variable is assigned to the reference of the string data allocated by Console.ReadLine and filled with the input.

Step 2 The int.TryParse static method tests for a numeric value, and if this test succeeds we can then use the integer.

Step 3 This program tries to multiply an integer value received by the user by 10 and display the product.

using System;

class Program
{
    static void Main()
    {
        // Step 1: read string from console.
        Console.WriteLine("Type an integer:");
        string line = Console.ReadLine();

        // Step 2: try to parse the string as an integer.
        int value;
        if (int.TryParse(line, out value))
        {
            // Step 3: multiply the integer and display it.
            Console.Write("Multiply integer by 10: ");
            Console.WriteLine(value * 10);
        }
        else
        {
            Console.WriteLine("Not an integer!");
        }
    }
}Type an integer:
4356
Multiply integer by 10: 43560

Note, finally

We can insert a Console.ReadLine method call at the end of the Main method—or even in a finally block in the Main method. This will keep the terminal window open.

Summary

With the Console.ReadLine method, part of the System namespace, we can get a string from the console window. We can use the string to control a loop or exit the program.