If的三种基础结构

if的三种基础结构

import java.util.Scanner;

//if单选择
public class IfDoem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("请输入内容：");
        String str = scanner.nextLine();
        //equals 判断字符串是否相等
        if(str.equals("hello")){
            System.out.println("ok");
        }
            System.out.println("error");

        scanner.close();
    }
}

import java.util.Scanner;

//if-else 双选择结构
public class IfDemo02 {
    //考试大于60分显示及格，小于60分显示不及格
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入你的分数：");

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

import java.util.Scanner;
//if else-if else-if......多选择结构
public class IfDemo03 {
    //判断每个分数段等级
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入您的分数：");
        int scores = scanner.nextInt();
        if (scores <= 100 && scores > 90){
            System.out.println("你的分数等级为："+"A");
        } else if (scores <= 90 && scores > 80) {
            System.out.println("你的分数等级为："+"B");
        } else if (scores <= 80 && scores >60) {
            System.out.println("你的分数等级为："+"C");
        } else if (scores <= 60) {
            System.out.println("你的分数等级为："+"D");
        }else {
            System.out.println("成绩不合法");
        }
        scanner.close();
    }
}