Convert

/*
 * 引用PresentationCore\PresentationFramework\System\Windows
 * 代码文件JustDoIt.cs
 */

using System;
using System.Windows;

public class Addition
{
    public static void Main()
    {
        int number1, number2;
        int sum;

        Console.WriteLine("{0}", "Please enter the first integer:");
        number1 = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("{0}", "Please enter the second integer:");
        number2 = Convert.ToInt32(Console.ReadLine());

        sum = number1 + number2;
        Console.WriteLine("{0} + {1} = {2}.", number1, number2, sum);

        Application app = new Application();
        app.Run();
    }
}

How to use the "Convert"?