Java流程控制04：if选择结构-526互联

一、if单选择结构

二、if双选择结构

import java.util.Scanner;

public class ifDemo02 {
    public static void main(String[] args) {
        //考试分数大于60就是及格，小于60就不及格
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入成绩：");

        int i = scanner.nextInt();
        if(i >= 60){
            System.out.println("及格");
        }else {
            System.out.println("不及格");
        }
        scanner.close();
    }
}

三、if多选择结构

;

import java.util.Scanner;

public class ifDemo03 {
    public static void main(String[] args) {
        //考试分数大于60就是及格，小于60就是不及格
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入成绩：");
        int score = scanner.nextInt();

        if(score == 100){
            System.out.println("恭喜满分");
        }else if(score<100 && score>=90){
            System.out.println("A级");
        }else if(score<90 && score>=80){
            System.out.println("B级");
        }else if(score<80 && score>=70){
            System.out.println("C级");
        }else if(score<70 && score>=60){
            System.out.println("D级");
        }else if(score<60 && score>=0){
            System.out.println("不及格");
        }else {
            System.out.println("成绩不合法");
        }
        scanner.close();
    }

四、嵌套的if结构

五、switch多选结构

public class SwitchDemo01 {
    public static void main(String[] args) {
        //case
        char grade = 'C';
        switch(grade){
            case 'A':
                System.out.println("优秀");
                break;
            case 'B':
                System.out.println("良好");
                break;
            case 'C':
                System.out.println("及格");
                break;
            case 'D':
                System.out.println("再接再厉");
                break;
            case 'E':
                System.out.println("挂科");
                break;
            default:
                System.out.println("未知等级");
        }

    }
}

public class SwitchDemo02 {
    public static void main(String[] args) {
        String name = "秦疆";  //JDK7以后才支持switch后面加字符串

        switch(name){
            case "秦疆":
                System.out.println("秦疆");
                break;
            case "狂神":
                System.out.println("狂神");
                break;
            default:
                System.out.println("弄啥勒！！！！");
        }
    }
}