面向对象程序设计（java）课堂代码
HelloProj1
HelloWorld.java
package com.study.hello;
public class HelloWorld1 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("Hello, Java World!\n"+
"tql"
); //换行输出+字符串连接‘+’
}
}
HelloProj2
HelloWorld2.java
package com.study.hello;
import java.util.Scanner;
public class HelloWorld2 {
public static String input() {
Scanner obj = new Scanner(System.in); //面板输入
String aName = "";
try {
System.out.print("Please input your name: ");
aName = obj.next();
} catch (Exception e) {
//异常处理
aName = "nobody";
} finally {
//最后
obj.close(); //关闭
}
return aName;
}
public static void output(String pName) {
System.out.println("Hello, " + pName);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
String myName;
myName = input();
output(myName);
}
}
HelloProj3
Greeting.java
package com.study.hello;
import java.util.Scanner;
public class Greeting {
private String aName;
private boolean flag = false; //用来判断是否使用input()
public void input() {
flag = true;
Scanner obj = new Scanner(System.in);
try {
System.out.print("Please input your name: ");
aName = obj.nextLine();
} catch (Exception e) {
aName = "nobody";
} finally {
obj.close();
}
}
public void output() {
if(flag) //如果使用了，即aName有值，输出即可
System.out.println("Hello, " + aName);
else
System.out.println("Hello, nobody");//没有值输出nobody
}
}
HelloWorld3.java
package com.study.hello;
public class HelloWorld3 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Greeting obj = new Greeting();
// obj.input();
obj.output();
}
}
ScoresProj
ScoreTransfer.java
package com.study.socres;
public class ScoreTransfer {
public void transfer(String pGrade) {
int score;
switch(pGrade) {
case "A": score = 95; break;
case "B": score = 85; break;
case "C": score = 75; break;
case "D": score = 65; break;
case "E": score = 35; break;
default: score = 0;
}
System.out.println("The score is "+ Integer.toString(score));
}
public void transfer(int pScore) {
String grade;
if (pScore <= 100 && pScore >= 90) {
grade = "A";
} else if (pScore >= 80 && pScore < 90) {
grade = "B";
} else if (pScore >= 70 && pScore < 80) {
grade = "C";
} else if (pScore >= 60 && pScore < 70) {
grade = "D";
} else if (pScore >= 0 && pScore < 60) {
grade = "E";
} else {
grade = "Error";
}
System.out.println("The grade is " + grade);
}
}
MainClass.java
package com.study.socres;
public class MainClass {
public static void main(String[] args) {
// TODO Auto-generated method stub
ScoreTransfer obj = new ScoreTransfer();
obj.transfer("E");
}
}
SavingMoney
Saver.java
package com.study.savingMoney;
public class Saver {
private double initial;
private double increase;
private int months;
private double[] saved;
// constructor
public Saver() {
//构造函数
this.initial = 100;
this.increase = 50;
this.months = 12;
this.saved = new double[this.months];
this.compute();
}
public Saver(double pInitial, double pIncrease, int pMonths) {
//重载
this.initial = pInitial;
this.increase = pIncrease;
this.months = pMonths;
this.saved = new double[this.months];
this.compute();
}
private void compute() {
this.saved[0] = this.initial;
for (int i = 1; i < this.months; i++) {
this.saved[i] = this.saved[i - 1] + this.increase;
}
}
public void showResult(boolean withMonthSave) {
double total = 0;
int i = 0;
while (i < this.saved.length) {
//数组的长度
if (withMonthSave) {
System.out.println("Saved: " + this.saved[i]);
}
total += this.saved[i];
i++;
}
System.out.println("Total saved: " + total);
}
public void showResult() {
double total = 0;
saved = new double[20]; for (double every : saved) {
System.out.println("Saved: " + every);
total += every;
}
System.out.println("Total saved: " + total);
}
}
MainClass.java
package com.study.savingMoney;
public class MainClass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Saver obj = new Saver();
obj.showResult();
}
}
FileProj
注意：如果你的“Workspace”是默认路径，那么本节课代码运行后，“MyData.txt”的路径为：C:\Users\用户名\eclipse-workspace\FileProj。
FileOp.java
注意：我第一次的文件读写跟老师的是不一样的，我自己写的，可以用作参考。
package com.study.files;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;
public class FileOp {
private String fileName;
public FileOp(String fileName) {
super();
this.fileName = fileName;
}
public FileOp() {
this.fileName = ".\\MyData.txt";
}
public void writeFile() {
// 写入
String[] companies = {
"Intel", "Microsoft", "IBM", "Oracle" };
try {
FileWriter fw = new FileWriter(this.fileName); // 打开文件
BufferedWriter bw = new BufferedWriter(fw); // 缓存区，提高效率
for (String line : companies) {
bw.write(line);
// bw.write("\n");
bw.newLine();
}
System.out.println("File saved.");
bw.close();
fw.close();
} catch (IOException e) {
// 异常
e.printStackTrace();
}
}
public void readFile() {
// 读取
ArrayList<String> companes = new ArrayList<String>();
String line;
try {
FileReader fr = new FileReader(this.fileName);
BufferedReader br = new BufferedReader(fr);
while ((line = br.readLine()) != null) {
companes.add(line); // 将每一行添加进companes
// System.out.println(line); // 输出文件中每一行
}
for(String comp : companes) {
//从ArrayList中读取每一行
System.out.println(comp);
}
// for (int i = 0; i < 4; i++) { //只有四行，具体情况具体分析
br.readLine();
// System.out.println(br.readLine()); //输出文件中每一行
// }
// System.out.println("File -- saved."); // 区分读取和写入
// for (int i = 0; i < companes.size(); i++) { // 从ArrayList中读取每一行，老师的说上面的while和for each
// System.out.println(companes.get(i));
// }
br.close();
fr.close();
} catch (IOException e) {
// 异常
e.printStackTrace();
}
}
}
MainClass.java
package com.study.files;
public class MainClass {
public static void main(String[] args) {
// TODO Auto-generated method stub
FileOp obj = new FileOp();
obj.writeFile();
obj.readFile();
}
}
CarGameProj
Car.java
package com.study.carGame;
import java.util.Random;
public class Car {
private String owner;
private String color;
private double speed;
private int duration;
// 默认构造函数 default constructor
public Car() {
this.owner = "Rocky";
this.color = "red";
this.speed = 0.0;
this.duration = 100;
}
// 有参构造函数 parameter constructor
public Car(String owner, String color) {
this.owner = owner;
this.color = color;
this.speed = 0.0;
this.duration = 100;
}
// 展示当前车的信息
public void show() {
System.out.println(" ********** car information **********");
System.out.println("Owner: " + this.owner);
System.out.println("Color: " + this.color);
System.out.println("Speed: " + this.speed);
System.out.println("Duration: " + this.duration);
System.out.println(" *************************************");
}
public void speedUp() {
// 加速函数
Random obj = new Random(); // 随机函数
this.speed += obj.nextDouble() * 10; // 随机生成一个double类的值
}
public void speedDown() {
// 减速函数
Random obj = new Random(); // 随机函数
this.speed -= obj.nextDouble() * 10; // 随机生成一个double类的值
if (this.speed <= 0.0) {
// 速度是大于等于0的
this.speed = 0.0;
}
}
public void crash() {
// 碰撞造成耐久损失
Random obj = new Random();
// this.duration -= (obj.nextInt(10) + 1);//随机生成整数0-指定的值，但不包括指定的值
if (this.duration <= 0) {
System.out.println(this.owner + " lost the car."); // 车报废，说明
}
if (this.speed < 5) {
// 复杂一点的设计 ,这部分不是老师写的
this.duration -= (obj.nextInt(10) + 1);
this.speed--;
} else if (this.speed > 5) {
this.duration -= (obj.nextInt(8) + 1);
this.speed -= 3;
} else if (this.speed > 10) {
this.duration -= (obj.nextInt(6) + 1);
this.speed -= 8;
} else if (this.speed > 15) {
this.duration -= (obj.nextInt(4) + 1);
this.speed -= 13;
}
}
// public void
}
Game.java
package com.study.carGame;
import java.util.Scanner;
public class Game {
private Car obj1;
private Car obj2;
public void showMenu() {
Scanner obj = new Scanner(System.in);
int sel;
while(true) {
// Show an operation menu
System.out.println(" ---------- Car Game ----------");
System.out.println(" 1 -- Get two new cars");
System.out.println(" 2 -- Speed up");
System.out.println(" 3 -- Speed down");
System.out.println(" 4 -- Crash!");
System.out.println(" 0 -- Exit");
System.out.println(" -----------------------------");
// get a choice
do {
//do-while 先进行一次操作，再进行判断是否继续进行操作
System.out.print(" Please input your choice:");
try {
sel = obj.nextInt();
}catch(Exception e) {
//设置sel =-1 可以使得while循环继续进行
sel = -1;
System.out.print(" Please input 0 - 4"); //提示
}
}while(sel<0 || sel>4); //循环条件不在 0 - 4之间
// switch-case for operations
switch(sel) {
//对每一种操作进行操作
case 0:
System.exit(0);//结束程序的函数
case 1:
obj1 = new Car("Tom", "Grey"); obj1.show();
obj2 = new Car("Jerry", "red"); obj2.show();
break;
case 2:
obj1.speedUp(); obj1.show();
obj2.speedUp(); obj2.show();
break;
case 3:
obj1.speedDown(); obj1.show();
obj2.speedDown(); obj2.show();
break;
case 4:
obj1.crash(); obj1.show();
obj2.crash(); obj2.show();
break;
}
}
}
}
MainClass.java
package com.study.carGame;
public class MainClass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Game obj = new Game();
obj.showMenu();
}
}
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