一、变量交换
int a = ;
int b = ;
Console.WriteLine("开始a={0},b={1}",a,b);
a = a + b;
b = a - b;
a = a - b;
Console.WriteLine("交换后a={0},b={1}",a,b);
二、Console.ReadLine()
Console.WriteLine("在输入语句前：");
string input = Console.ReadLine();
Console.WriteLine("在输入语句后。");
Console.WriteLine(input);