Java-流程控制（if-else）和（switch）-学习笔记04

if (条件){
	语句;
}
else if (条件){
	语句;
|
else{
	语句;
}

• 不加break;会让程序从目标case开一直执行到最后包括default情况下的语句

switch(表达式){
	case 常量表达式1:
		语句1; 
		break; 
	case 常量表达式2:
		语句2; 
		break;
	default: // 都不满足情况下用default
		语句3;
}

举个例子

Scanner sc = new Scanner(System.in);
System.out.print("Please input a number between 1-3: ")
int n = sc.nextInt();
switch (n){
	case 1:
		System.out.println("1");
		break;
	case 2:
		System.out.println("2");
		break;
	case 3:
		System.out.println("3");
		break;
	default:
		System.out.println("Out of range");
}

如果不用break;

Scanner sc = new Scanner(System.in);
System.out.print("Please input a number between 1-3: ");
int n = sc.nextInt();
switch (n){
	case 1:
		System.out.println("1");
	case 2:
		System.out.println("2");
	case 3:
		System.out.println("3");
	default:
		System.out.println("Out of range");
}

当你输入2会返回如下

Please input a number between 1-3: 2
2
3
Out of range