if语句的使用

import java.util.Scanner;

public class Day1 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);

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

        //equals 判断字符串是否相等
        if (i.equals("hello")){
            System.out.println(i);
        }
        else {
            System.out.println("End");
        }


        scanner.close();
    }
}

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import java.util.Scanner;

public class Day2 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        //考试分数大于60分就是及格，小于60分就是不及格

        System.out.println("请输入成绩:");
        int score=scanner.nextInt();

        if (score>60){
            System.out.println("及格");
        }else {
            System.out.println("不及格");
        }
        scanner.close();
    }
}

=========================================================================

import java.util.Scanner;

public class Day3 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        //考试分数大于60分就是及格，小于60分就是不及格

        System.out.println("请输入成绩:");
        int score=scanner.nextInt();

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