流程控制-选择结构

选择结构

• 课堂截图
  

If语句

代码1

package com.frey.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

代码2

package com.frey.struct;

import java.util.Scanner;

import javax.lang.model.util.ElementScanner6;

public class IfDemo02 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        System.out.println("请输入分数：");

        int i=scanner.nextInt();
        if (i==100)
        {
            System.out.println("恭喜满分");
        }
        else if (i<100 && i>=90)
        {
            System.out.println("A级");
        }
        else if (i<90&&i>=80)
        {
            System.out.println("B级");
        }
        else if (i<80&&i>=70)
        {
            System.out.println("C级");
        }
        else if (i<70&&i>=60)
        {
            System.out.println("D级");
        }
        else if (i<60 && i>=0)
        {
            System.out.println("不及格");
        }
        else 
        {
            System.out.println("无效输入！");
        }

        scanner.close();
    }
}

Switch语句

代码

package com.frey.struct;

public class SwitchDemo01 {
    public static void main(String[] args) {
        String s="cwx";
        switch (s) 
        {
            case "yjh" :
                System.out.println("yjh");
                break;
            case "cy" :
                System.out.println("cy");
                break;
            default:
                System.out.println("梦里啥都有");
        }
    }
}