3的值为true执行代码

}else{

//如果以上布尔表达式都不为true执行代码

}

public static void main(String[] args) {
//考试分数大于60就是及格，小于60就不及格
Scanner scanner = new Scanner(System.in);
System.out.println("请输入成绩");
double score = scanner.nextDouble();
if (score==100){
System.out.println("恭喜满分");
}else if (score>=90&&score<100){
System.out.println("A级");
}else if (score>=80&&score<90){
System.out.println("B级");
}else if (score>=70&&score<80){
System.out.println("C级");
}else if (score>=60&&score<70){
System.out.println("D级");
}else if (score>100||score<0){
System.out.println("成绩有误");
}else{
System.out.println("不及格");
}
scanner.close();
}


switch

case穿透：如果没有default程序会一直往下运行

public static void main(String[] args) {
//case穿透
char grade = 'C';
switch (grade){
case 'A':
System.out.println("优秀");
case 'B':
System.out.println("良好");
case 'C':
System.out.println("及格");
case 'D':
System.out.println("再接再厉");
default:
System.out.println("未知等级");
}
}


 

if多选择结构与switch_布尔表达式

 

public static void main(String[] args) {

    //case穿透

    char grade = 'C';


    switch (grade){

        case 'A':

            System.out.println("优秀");

            break;

        case 'B':

            System.out.println("良好");

            break;

        case 'C':

            System.out.println("及格");

            break;

        case 'D':

            System.out.println("再接再厉");

            break;

        default:

            System.out.println("未知等级");



    }

}

if多选择结构与switch_布尔表达式_02