return,break,continue

Return，退出整个函数Break,终止while循环，继续后面的代码；Continue,终止while本次循环，继续while后面的代码int sum = 0; int i = 0; while (i < =100) { sum = i + sum; i++; } Console.WriteLine("{0}",sum); Console.ReadKey();升级： int sum = 0; int i = 0; while (i<=100) { if (i % 7 == 0)//此处7不自增，永远都是7 { continue; } sum = i + sum; i++; } Console.WriteLine("{0}",sum); Console.ReadKey();正确：int sum = 0; int i = 0; while (i<=100) { if (i % 7 == 0)// { i++; continue; } sum = i + sum; i++; } Console.WriteLine("{0}",sum); Console.ReadKey();2.while (true) { Console.WriteLine("请输入用户名"); string username=Console.ReadLine(); Console.WriteLine("请输入密码"); string password = Console.ReadLine(); if (username == "admin" & password == "88888") { break; } }