if选择结构

 

 

 

package struct;

import java.util.Scanner;

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

        System.out.println("情输入内容：");
        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();
    }
}

 

 

package struct;

import java.util.Scanner;

public class IfDemo02 {
    public static void main(String[] args) {
        //考核分数大于60就及格，小于60就不及格
        Scanner scanner = new Scanner(System.in);

        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！");
        }

 

 

 

 

package struct;

import java.util.Scanner;

public class IfDemo03 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入成绩：");
        int score  = scanner.nextInt();
        if (score==100){
            System.out.println("恭喜满分!");
        }else if(score < 100 && score >= 90){
            System.out.println("A级");
        }else if(score < 90 && score >= 80){
            System.out.println("B级");
        }else if(score < 80 && score >= 70){
            System.out.println("C级");
        }else if(score < 70 && score >= 60) {
            System.out.println("D级");
        }else if(score < 60 && score >=0 ){
            System.out.println("不及格!");
        }else{
            System.out.println("成绩不合法！");//102
        }
    }
}