顺序结构，if，Switch选择结构

if单选择结构

if双选择结构

ifif多选择结构

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("满分");
        }else if (score<100 && score>80){
            System.out.println("A级");
        }else if(score<80 && score>60){
            System.out.println("B级");
        }else if (score<60){
            System.out.println("不及格");
        }else{
            System.out.println("成绩不合法");
        }
        scanner.close();
    }
}

public class SwitchDemo01 {
    public static void main(String[] args) {
        //case 穿透 //switch 匹配一个具体的值
        //字符的本质还是数字
        //反编译
        char grade = ‘C‘;

        switch (grade){
            case ‘A‘ :
                System.out.println("优秀");
                break;//可选
            case ‘B‘ :
                System.out.println("良");
                break;//可选
            case ‘C‘ :
                System.out.println("合格");
                break;//可选
            default:
                System.out.println("未知");
        }
    }
}