package org.example;
import java.util.Scanner; // 修正分号
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
// 读取输入并创建分数对象
Fraction a = new Fraction(in.nextInt(), in.nextInt());
Fraction b = new Fraction(in.nextInt(), in.nextInt());
// 输出原始分数
a.print();
b.print();
// 加法运算
a.plus(b).print();
// 组合运算：a * b + 5/6
a.multiply(b).plus(new Fraction(5, 6)).print();
// 再次输出原始分数（验证是否被修改）
a.print();
b.print();
in.close();
}
}
// 示例 Fraction 类（需补充完整实现）
class Fraction {
private int numerator;
private int denominator;
public Fraction(int numerator, int denominator) {
if (denominator == 0) {
throw new IllegalArgumentException("分母不能为0");
}
// 约分处理
int gcd = gcd(Math.abs(numerator), Math.abs(denominator));
this.numerator = numerator / gcd;
this.denominator = denominator / gcd;
// 确保分母为正数
if (this.denominator < 0) {
this.numerator = -this.numerator;
this.denominator = -this.denominator;
}
}
public void print() {
System.out.println(this.numerator + "/" + this.denominator);
}
public Fraction plus(Fraction other) {
int newNumerator = this.numerator * other.denominator + other.numerator * this.denominator;
int newDenominator = this.denominator * other.denominator;
return new Fraction(newNumerator, newDenominator);
}
public Fraction multiply(Fraction other) {
int newNumerator = this.numerator * other.numerator;
int newDenominator = this.denominator * other.denominator;
return new Fraction(newNumerator, newDenominator);
}
// 求最大公约数的私有方法
private int gcd(int a, int b) {
while (b != 0) {
int temp = b;
b = a % b;
a = temp;
}
return a;
}
}这个构造函数是不需要返回类型的。
根据参数的不同调用不同的函数。
成员变量需要用this在成员函数中调用。
如果一个类你想让他在所有文件中都能访问，定义为pulic,并且所在文件以其类名命名。
如果一个函数前面没有限定为private public,那么限定符是friendly,这个函数只能是该类所在包的其他类才能访问。如果想继续访问，那么只能import该函数的包进来。
如果不导入包，那么只能是包名.类名这样使用全名。
装父类的容器，也可以装改父类的子类。
而且子类对象赋值给父类的时候，叫向上造型。
Java是单根结构。都是obejct继承的。
package org.面向对象;
import java.util.HashMap;
import java.util.Scanner;
public class Game {
private Room currentRoom;
private HashMap<String, Hanlder> handlers = new HashMap<>();
public Game()
{
handlers.put("go", new HandlerGo(this));
handlers.put("bye", new HandlerBye(this));
handlers.put("help", new HandlerHelp(this));
System.out.println("Handlers: " + handlers); // 调试输出
createRooms();
}
private void createRooms()
{
Room outside, lobby, pub, study, bedroom;
// 制造房间
outside = new Room("城堡外");
lobby = new Room("大堂");
pub = new Room("小酒吧");
study = new Room("书房");
bedroom = new Room("卧室");
// 初始化房间的出口
outside.setExit("east", lobby);
outside.setExit("south", pub);
outside.setExit("west", study);
lobby.setExit("west", outside);
lobby.setExit("up", study);
pub.setExit("north", outside);
study.setExit("east", outside);
study.setExit("south", bedroom);
study.setExit("down", pub);
bedroom.setExit("east", study);
bedroom.setExit("north", lobby);
currentRoom = outside; // 从城堡门外开始
}
// 封装房间出口初始化逻辑
private void printWelcome() {
System.out.println();
System.out.println("欢迎来到城堡！");
System.out.println("这是一个超级无聊的游戏。");
System.out.println("如果需要帮助，请输入 'help' 。");
System.out.println();
hint();
}
private void hint() {
System.out.println(currentRoom.getExitDesc()) ;
}
// 以下为用户命令
public void goRoom(String direction)
{
Room nextRoom = currentRoom.getNextRoom(direction);
if (nextRoom == null) {
System.out.println("那里没有门！");
}
else {
currentRoom = nextRoom;
hint();
}
}
public void play() {
while (true) {
System.out.println(currentRoom.description);
System.out.print("> ");
Scanner in = new Scanner(System.in);
String line = in.nextLine();
String[] words = line.split(" ");
String value = "";
if(words.length > 1) {
value = words[1];
}
else {
value = words[0];
}
Hanlder hanlder = handlers.get(words[0]);
System.out.println("Input command: " + words[0]);
System.out.println("Handlers map: " + handlers);
if(hanlder != null) {
hanlder.doCmd(value);
if(hanlder.isBye(value)) {
break;
}
} else{
System.out.println("无效的命令！");
this.printWelcome();
}
}
}
public static void main(String[] args) {
Game game = new Game();
game.printWelcome();
game.play();
}
}
Hanlder hanlder = handlers.get(words[0]);
System.out.println("Input command: " + words[0]);
System.out.println("Handlers map: " + handlers);
if(hanlder != null) {
hanlder.doCmd(value);
if(hanlder.isBye(value)) {
break;
}
} else{
System.out.println("无效的命令！");
this.printWelcome();
}
这里hanlder.isBye如果想调用到正确的子类hanlderBye的isBye,那么子类重载如下，记得添加 @Override，函数参数也要和父类一致。
package org.面向对象;
public class HandlerBye extends Hanlder{
public HandlerBye(Game game) {
super(game);
}
@Override
public boolean isBye(String cmd)
{
return true;
}
}
--------------------------以上代码主要是想调用相应的辅助类，而不是硬编码，这样有新的命令只需向handler里添加新的
辅助类，比如HandlerWW等。
public Game()
{
handlers.put("go", new HandlerGo(this));
handlers.put("bye", new HandlerBye(this));
handlers.put("help", new HandlerHelp(this));
System.out.println("Handlers: " + handlers); // 调试输出
createRooms();
}
辅助类定义如下
package org.面向对象;
public abstract class Hanlder {
protected Game game;
public Hanlder(Game game){
this.game = game;
}
public void doCmd(String cmd){}
public boolean isBye(String cmd){
return false;
}
}
-----------------------------------
package org.面向对象;
public class HandlerBye extends Hanlder{
public HandlerBye(Game game) {
super(game);
}
@Override
public boolean isBye(String cmd)
{
return true;
}
}
-----------------------------
package org.面向对象;
public class HandlerGo extends Hanlder {
public HandlerGo(Game game) {
super(game);
}
@Override
public void doCmd(String word)
{
game.goRoom(word);
}
}
--------------------------
package org.面向对象;
public class HandlerHelp extends Hanlder {
public HandlerHelp(Game game) {
super(game);
}
@Override
public void doCmd(String word) {
System.out.println("Help 命令");
System.out.println(" help - 显示帮助");
System.out.println(" bye - 退出游戏");
System.out.println(" look - 显示当前房间");
System.out.println(" go <方向> - 移动到指定方向的房间");
System.out.println(" take <物品> - 从房间中取走物品");
System.out.println(" drop <物品> - 丢弃物品");
}
}