java by example_lab3

7/27/2019 Java By Example_lab3

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Java by Example lab 3

2009 FPT-Aptech Trang 1 / 5

I - Chun b: Kin thc cn c: Khi nim Class, Object, Field, Property, Method, Constructor. Knng cn rn luyn:

Tp vit mt chng trnh bng Java:o t tn v khai bo Class.o Bit cch xy dng Class, khi to v s dng object trong Java.o Cch s dng cc t khapublic, private, static.o Trnh by code.o Cch chy v gli chng trnh.

Tp gii quyt bi ton di gc lp trnh hng i tng.

II - Ni dung:

Phn 1: Workshop- Lm li phn workshop ca module 4 trn a.

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Phn 2: Vit li cc class sau v sa ht li cho chng trnh:/**

* @(#)Student.java

*

*

* @author

* @version 1.00 2009/1/19

*/

import java.util.Scanner;

public class Student {

//khai bao cac truong(field)

private int id;

private String name;

private boolean gender;

//constructor khong co doi so

public Student() {

this.id=-1;this.name="noname";

this.gender=true;

}

//constructor co doi so

public Student(int id,String name,boolean gender) {

this.id=id;

this.name=name;

this.gender=gender;

}

//get accessor

public int getId() {

return this.id;

}

public void setId(int value) {

this.id=value;

}

public String getName() {

return this.name;

}

public void setName(String value) {

this.name=value;

}

public boolean isMale() {

return this.gender;

}public void setMale(boolean value) {

this.gender=value;

}//To be continued...



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/**

* @(#)Main.java

*

*

* @author

* @version 1.00 2009/1/3

*/

public class Main {

public static void main(String[] args) {

//tao doi tuong cua lop student

Student std=new Student();

//goi phuong thuc cua doi tuong student

std.scanInfo();

std.printInfo();

}

}

//phuong thuc nhap

public void scanInfo() {

Scanner input=new Scanner(System.in);System.out.print("Enter ID:");

this.id=input.nextInt();

System.out.print("Enter Name:");

this.name=input.nextLine();

System.out.print("Enter Gender:");

this.gender=input.nextBoolean();

}

public void printInfo() {

System.out.println("-----------------------------------");

System.out.println("| ID | Name | Male |");

System.out.printf("| %d | %s | %b |\n",this.id,this.name,this.gender);

}

}



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Phn 3: Bi tp tlm3.1. Vit cc Class da theo s sau:

- Lu : vi mi thuc tnh ca class Person, cn khai bo 1 field, v 1 cp phng thc get, set tngng. V d: vi thuc tnh ID, ta cn khai bo trong class Person nh sau:

//Cch ci t thuc tnh ID:privateint id; //field ny dnglu thng tin vID ca PersonpublicintgetID() {

return this.id;

}

publicvoidsetID(int value) {

this.id=value;}

a. Sau khi xy dng xong cc thuc tnh ca class Person, hy vit: 1 Constructor khi to cc gi tr ban u cho cc thuc tnh ID, FirstName, LastName 1 Constructor khc khi to gi tr cho cc thuc tnh ID, FirstName, LastName, Email,

Phone.

1 Constructor khng cha tham s.

b. Vit 2 phng thc printInfo() v scanInfo(), trong : printInfo() dng in thng tin ca Person theo nh dng sau:

---------------------------------------------------------------------------

| ID | First Name | Last Name | Email | Phone |---------------------------------------------------------------------------

scanInfo() dng nhp thng tin Person t console theo th t nh sau:Nhp ID:...Nhp FirstName:...Nhp LastName:...Nhp Email:...Nhp Phone:...

3.2. Vit mt Main Class (class cha hm main )vi tn l Main nh trn s.Trong hm main, vit chng trnh th hin menu sau:===Menu===

1. To mi mt object Person dng constructor.



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2. Cp nht thuc tnh ca object va to bng phng thc scanInfo().3. Hin th thng tin object va to bng phng thc printInfo().4. Thay i thuc tnh Email ca object va to.

5. Thot.#Chn:

3.3. Vit cc class theo s sau:

a. Sau khi xy dng cc thuc tnh ca class Rectangle, hy vit: 1 Constructor khi to cc gi tr ban u cho cc thuc tnh x, y, width, height. 1 Constructor khng cha tham s, v gn gi tr mc nh cho x=0, y=0, witdh=10,

height=10.

b. Vit 2 phng thc printInfo() v scanInfo(), trong : printInfo() dng in thng tin ca mt Rectangle theo nh dng sau:

// v d hnh chnht c cnh width=12, height=3 th in nhsau:************

************************

scanInfo() dng nhp thng tin ca mt Rectangle t console theo th t nh sau:Nhp x:Nhp y:Nhp width:Nhp height:

c. Vit mt Main Class (class cha hm main )vi tn l Main nh trn s.Trong hm main, vit chng trnh th hin menu sau:===Menu===

6. To mi mt hnh ch nht dng constructor.

7. Cp nht thuc tnh ca hnh va to bng phng thc scanInfo()8. V hnh ch nht va to bng phng thc printInfo()9. Thot.

#Chn:

3.4. Lm bi assignment 4 trong a CD.


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