javaSE第五课 顺序结构和选择结构

import java.util.Scanner;

public class Day4 {
    public static void main(String[] args) {
        
        System.out.println("1");
        System.out.println("2");
        System.out.println("3");
        
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        //if单选择结构
        if(str.equals("hello")){
            System.out.println(str);
        }
        System.out.println("===============");
        //if双选择结构
        int a=scanner.nextInt();
        if(a<60){
            System.out.println("考试不及格");
        }else {
            System.out.println("考试及格");
        }
        System.out.println("===============");
        
        int i=scanner.nextInt();
        if(i==100){
            System.out.println("很棒，满分！");
        }else if(i>=60&&i<100){
            System.out.println("及格，不错！");
        }else {
            System.out.println("不及格，继续努力！");
        }
        System.out.println("====================");
        
        char grade = 'c';
        switch (grade){
            case 'a':
                System.out.println("优秀");
                break;//找到符合的条件跳出switch
            case 'b':
                System.out.println("良好");
                break;
            case 'c':
                System.out.println("及格");
                break;
            case 'd':
                System.out.println("不及格");
                break;
            //没有找到以上匹配的字母等级
            default:
                System.out.println("未知等级");
        }
        System.out.println("==================");
        
        String str1="大帅哥";
        switch (str1){
            case "大帅哥":
                System.out.println("就是我");
                break;
            case "大漂亮":
                System.out.println("那是你");
                break;
            case "大能耐":
                System.out.println("啥也不是");
                break;
        }
        System.out.println("End");
        scanner.close();
    }
}