Java-examples

Phone รุ่นแรก (ก่อนเบรค)

Phone.java

<geshi lang="java"> public class Phone { private double credit; Phone(double inCredit) { credit = inCredit; } public double getCredit() { return credit; } public void setCredit(double credit) { this.credit = credit; } public void call(double minute) { credit -= callCost(minute); } protected double callCost(double minute) { return 0; } } </geshi>

PrepaidPhone.java

<geshi lang="java"> public class PrepaidPhone extends Phone {

PrepaidPhone(double inCredit) { super(inCredit); }

protected double callCost(double minute) { if(minute <= 1) return 1; else return 1 + (minute - 1) * 0.5; } } </geshi>

PostpaidPhone.java

<geshi lang="java"> public class PostpaidPhone extends Phone {

PostpaidPhone(double inCredit) { super(inCredit); }

public double callCost(double minute) { return minute * 0.25; } } </geshi>

Phone รุ่นสอง (หลังเบรค)

input/output

phone.dat
---------
3
prepaid#0812345678:1000.00
postpaid#0823456789:50
prepaid#0888888888:20000000

call.dat
--------
0812345678:5
0812345678:2
0823456789:1.5
0888888888:300
0823456789:12.5
0823456789:40.2

output
------
0812345678:954
0823456789:15.2
0888888888:199992323.5

Codes

Phone.java

<geshi lang="java"> public class Phone { private double credit; private String number; Phone(String num, double inCredit) { credit = inCredit; number = num; } Phone(String raw) { decode(raw); } public void decode(String raw) { // ... }

public void call(double minute) { credit -= callCost(minute); } double callCost(double minute) { return 0; }

public double getCredit() { return credit; } public void setCredit(double credit) { this.credit = credit; } public String getNumber() { return number; } } </geshi>

PrepaidPhone.java

<geshi lang="java"> public class PrepaidPhone extends Phone {

public PrepaidPhone(String raw) { super(raw); }

PrepaidPhone(String num, double inCredit) { super(num, inCredit); }

protected double callCost(double minute) { if(minute <= 1) return 1; else return 1 + (minute - 1) * 0.5; } } </geshi>

PostpaidPhone.java

<geshi lang="java">

public class PostpaidPhone extends Phone {

public PostpaidPhone(String raw) { super(raw); }

PostpaidPhone(String num, double inCredit) { super(num, inCredit); }

public double callCost(double minute) { return minute * 0.25; } } </geshi>

PhoneMain.java

<geshi lang="java"> public class PhoneMain {

static Phone buildPhone(String raw) { String [] results = raw.split("#"); if(results[0].equals("prepaid")) return new PrepaidPhone(results[1]); else return new PostpaidPhone(results[1]); }

static Phone findPhone(Phone [] phones, String num) { for(int i=0; i<phones.length; i++) if(phones[i].getNumber().equals(num)) return phones[i]; return null; }

static Phone [] readPhoneData() throws Exception { BufferedReader in = new BufferedReader( new FileReader("c:/phone.dat")); int phoneCount = Integer.parseInt(in.readLine()); Phone [] phones = new Phone[phoneCount]; for(int i=0; i<phoneCount; i++) { String line = in.readLine(); phones[i] = buildPhone(line); } return phones; }

public static void main(String [] argv) { } } </geshi>