题目：请输入星期几的第一个字母来判断一下是星期几，如果第一个字母一样，则继续 判断第二个字母。
public class Week { public static void main(String[] args) { System.out.println("请输入字母："); Scanner s = new Scanner(System.in); String d1 = s.nextLine(); switch (d1) { case "M": System.out.println("Monday!"); break; case "W": System.out.println("Wednesday!"); break; case "F": System.out.println("Friday!"); break; case "T": String d2 = s.nextLine(); if(d2.equals("u")) System.out.println("Tuesday!"); else if(d2=="h") System.out.println("Thurday!"); else System.out.println("No day!"); break; case "S": String d3 = s.nextLine(); if(d3.equals("a")) System.out.println("Saturday!"); else if(d3=="u") System.out.println("Sunday!"); else System.out.println("No day!"); break; default: System.out.println("输入有误..."); break; } } }