IF与Switch的选择结构使用

IF与Switch的结构

IF单选择结构

package com.JIE.struct;

import java.util.Scanner;

public class IfDemo01 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("请输入内容：");
        String s = scanner.nextLine();

        //equals：判断字符串是否相等
        if (s.equals("Hello")){
            System.out.println(s);
        }
        System.out.println("end");

        scanner.close();
    }
}

.equals：判断字符串是否相等

IF选择结构

package com.JIE.struct;

import java.util.Scanner;

public class IfDemo02 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入成绩");
        int i = scanner.nextInt();
        if (i==100){
            System.out.println("优秀");
        }else if(i<100 && i>=90) {
            System.out.println("A");
        }else if(i>=80 && i<=90) {
            System.out.println("B");
        }else if(i>=70 && i<=80) {
            System.out.println("C");
        }else if(i>=60 && i<70) {
            System.out.println("D");
        }else if(i<60 && i>=0){
            System.out.println("成绩不合格");
        }else {
            System.out.println("输入不合法");
        }
        scanner.close();
    }
}

编写代码时，一定要严谨！

嵌套循环判断

public class IfDemo03 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入查找名：");
        String i = scanner.next();
        if (i.equals("张泽龙")){
            System.out.println("请输入成绩：");
            int o = scanner.nextInt();
            if (o>=600){
                System.out.println("恭喜考入带本成为 人上人上人");
            }else if(o<600 && o>=300){
                System.out.println("恭喜考入带专 成为人上人");
            }else {
                System.out.println("来世再做带专人");
            }
        }else {
            System.out.println("输入有误");
        }
       scanner.close();
    }
}

Switch多选择结构

public class Switch {
    public static void main(String[] args) {
        //switch 匹配一个具体的值
        char grade = 'A';

        switch (grade){
            case'A': //case穿透  不加break结束则会全部输出
                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;
            default:
                System.out.println("未知等级");
        }
    }
}

本文地址：https://blog.csdn.net/JIE1870586378/article/details/110260768