if 和 else

else 为不满足任意条件时执行

package com.mek.demo;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // 创建一个Scanner实例对象
        Scanner scanner = new Scanner(System.in);

        System.out.println("input passwd:");

        String passwd = scanner.nextLine();
        // equals 字符串比较
        if(passwd.equals("admin")){
            System.out.println("passwd Yes!");
        }else {
            System.out.println("passwd Fail!");
        }



        // 关闭Scanner实例对象
        scanner.close();

    }
}

if和else if 嵌套

多条件判断

package com.mek.demo;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // 创建一个Scanner实例对象
        Scanner scanner = new Scanner(System.in);

        System.out.println("input your wallet(int class):");

        int wallet = scanner.nextInt();

        if(wallet >= 500000){
            System.out.println("affluence!");
        }else if (wallet >= 200000){
            System.out.println("ordinary!");
        }else if (wallet >= 100000){
            System.out.println("So so!");
        }else if (wallet >= 50000){
            System.out.println("poor!");
        }else {
            System.out.println("Go to hell!");
        }

        // 关闭Scanner实例对象
        scanner.close();

    }
}