---
title: "00-判断语句"
created: 2025-12-02
tags:
  - 项目
aliases:
  - 判断语句
---
# 判断语句

## if-else语句

与C++、Python中类似。

例如：

```java
package com.yxc;

import java.util.Scanner;

public class Main {
   public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       int year = sc.nextInt();
       if (year % 100 == 0) {
           if (year % 400 == 0)
               System.out.printf("%d是闰年\n", year);
           else
               System.out.printf("%d不是闰年\n", year);
       } else {
           if (year % 4 == 0)
               System.out.printf("%d是闰年\n", year);
           else
               System.out.printf("%d不是闰年\n", year);
       }
   }
}
```

## switch语句

与C++中类似。

```java
package com.yxc;

import java.util.Scanner;

public class Main {
   public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       int day = sc.nextInt();
       String name;
       switch (day) {
           case 1:
               name = "Monday";
               break;
           case 2:
               name = "Tuesday";
               break;
           case 3:
               name = "Wednesday";
               break;
           case 4:
               name = "Thursday";
               break;
           case 5:
               name = "Friday";
               break;
           case 6:
               name = "Saturday";
               break;
           case 7:
               name = "Sunday";
               break;
           default:
               name = "not valid";
       }
       System.out.println(name);
   }
}
```

## 逻辑运算符与条件表达式

与C++、Python类似。

例如：

```java
package com.yxc;

import java.util.Scanner;

public class Main {
   public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       int year = sc.nextInt();
       if (year % 100 != 0 && year % 4 == 0 || year % 400 == 0)
           System.out.printf("%d是闰年\n", year);
       else
           System.out.printf("%d不是闰年\n", year);
   }
}
```

注意一点是 java中 int不能作为bool值来判断

所以不能写成 year % 100 && year % 4== 0 || year % 400 == 0

## 练习题

      [[2-Learning/05-项目/04-SpringBoot框架课/01-java语法/02-判断语句/01-倍数.md|倍数]]
  [[05-零食|零食]]

[[03-区间|区间]]
[[04-游戏时间|游戏时间]]  [[02-动物|动物]]

---

**项目分区导航**： [[05-钞票|钞票]] ⬅️ | 00-判断语句 |  ➡️ [[01-倍数|倍数]]