「java类与对象编程题」java类与对象编程题哪个难
今天给各位分享java类与对象编程题的知识，其中也会对java类与对象编程题哪个难进行解释，如果能碰巧解决你现在面临的问题，别忘了关注本站，现在开始吧！
本文目录一览：
- 1、用JAVA编程 类与对象的基础题
- 2、java编程题目，求求大佬救救我
- 3、有关java编程题目？
- 4、谁能提供JAVA 类和对象的练习题!!
- 5、有一道 java面向对象编程题 求大家帮我写一下 面向对象基础 看到迷茫
用JAVA编程 类与对象的基础题
class Phone{
private String phonenumber;
public void setPhonenumber(String phonenumber){
this.phonenumber=phonenumber;
}
public String getPhonenumber(){
return phonenumber;
}
public void recCall(){
System.out.println("接到一个电话");
}
public void telCall(){
System.out.println("拨出一个电话");
}
}class Fixedphone extends Phone{
private String phonenumber;//号码是私有，设置为private，不可继承
public void recCall(){
System.out.println("以"+this.phonenumber+"呼出了一个电话"); //重载了父类的recCall
}
}class Cordlessphone extends Fixedphone{
private String phonenumber;
public void info(){
System.out.println("这是无绳电话的信息");
}
}interface Moveable{
public void moveinfo();
}class Mobilephone extends Phone implements Moveable{
private String phonenumber;
public void moveinfo(){
System.out.println("我实现了可移动性");
}
}public class PhoneTest{
public static void main(String a[]){
Phone[] p=new Phone[5];
Phone p1=new Phone();
p1.setPhonenumber("123456789");
p[0]=p1;
Phone p2=new Phone();
p2.setPhonenumber("987654321");
p[1]=p2;
Mobilephone mp=new Mobilephone();
mp.setPhonenumber("11111");
p[2]=mp;
Fixedphone fp=new Fixedphone();
fp.setPhonenumber("22222");
p[3]=fp;
Cordlessphone cp=new Cordlessphone();
cp.setPhonenumber("33333");
p[4]=cp;
for(int i=0;ip.length;i++){
System.out.println(p[i].getPhonenumber());
} p[4]=p[1];
System.out.println(p[4].getPhonenumber());
}} 写的不是很好，希望对你有帮助噶
java编程题目，求求大佬救救我
这个题考察的是面向对象三大特性之一的继承。
子类继承父类。
项目结构如何所示：
Mobile 为父类，有一个属性：mobilePhone 代表电话号码。
有4个方法（功能）:
1、获取手机号码:public String getMobilePhone(){}
2、存储手机号码：public void setMobilePhone(String mobilePhone) {}
3、拨打电话号码：public void callOnMobilePhone(){}
4、挂断电话：public void callOffPhone(){}
具体代码如下所示：、
--------------------------------------mobilePhone 开始--------------------------------------
/**
* @author 冯修远
* 创建一个第一代手机类，要求包含手机号码信息，并包含获取电话号码，
* 存储电话号码、拨打电话号码和挂断电话等功能。并以此为父类，派生
* 出子类第二代手机类，增加拍照功能。以第二代手机类来生成对象并
* 模拟实现拨打电话、挂断电话拍照等功能。
*/
public class Mobile {
//手机号码
private String mobilePhone;
/**
* 获取手机号码
* @return
*/
public String getMobilePhone() {
return mobilePhone;
}
/**
* 存储手机号码
* @param mobilePhone
*/
public void setMobilePhone(String mobilePhone) {
this.mobilePhone = mobilePhone;
}
/**
* 拨打电话号码
*/
public void callOnMobilePhone(){
System.out.println("拨打电话号码:"+mobilePhone);
}
/**
* 挂断电话
*/
public void callOffPhone(){
System.out.println("挂断与:"+mobilePhone+"的通话");
}
}
--------------------------------------mobilePhone 结束--------------------------------------
PhotoMobile 为子类或者叫派生类，继承自父类：Mobile
同时也继承了父类的4个方法，但父类的属性因为我设置的是private,所以继承不了。
PhotoMobile 的代码如下图所示：
最后一个类，也就是测试类，用于创建第二代手机的对象，并调用相应的功能，如下图所示：
最终，程序的运行结果如下图所示：
我是冯修远，如果我的答案对您有帮助的话，请采纳以帮助更多的人，如果还有其它的问题，也请关注我，私信我，谢谢！
有关java编程题目？
按照题目要求编写的圆,圆锥和测试类的Java程序如下
Test.java文件内容如下
class Circle{
private double r;
private String color;
public Circle(double r){
this.r=r;
}
public double area(){
return Math.PI*r*r;
}
public double perimeter(){
return Math.PI*2*r;
}
public double getR(){
return this.r;
}
public void setR(double r){
this.r=r;
}
public String getColor(){
return this.color;
}
public void setColor(String color){
this.color=color;
}
public String toString(){
return "圆的半径为"+r+",颜色为"+color;
}
}
class Cone{
private Circle c;
private double h;
private String color;
public Cone(Circle c,double h){
this.c=c;
this.h=h;
}
public double volume(){
return 1.0/3*c.area()*h;
}
public Circle getCircle(){
return this.c;
}
public void setCircle(Circle c){
this.c=c;
}
public double getH(){
return this.h;
}
public void setH(double h){
this.h=h;
}
public String getColor(){
return this.color;
}
public void setColor(String color){
this.color=color;
}
public String toString(){
return "圆锥的底面积为"+c.area()+",高为"+h+",颜色为"+color;
}
}
public class Test{
public static void main(String[] args){
Circle circle1=new Circle(2.5);
circle1.setColor("红色");
System.out.println(circle1.toString());
System.out.println("圆的面积为"+circle1.area());
System.out.println("圆的周长为"+circle1.perimeter());
Cone circlar1=new Cone(circle1,2.7);
circlar1.setColor("蓝色");
System.out.println(circlar1.toString());
System.out.println("圆锥的体积为"+circlar1.volume());
}
}
谁能提供JAVA 类和对象的练习题!!
Question No: 1
public class test (
2. public static void main (String args[]) {
3. int i = 0xFFFFFFF1;
4. int j = ~i;
5.
6. }
7. )
What is the decimal value of j at line 5?
A. 0
B. 1
C. 14
D. –15
E. An error at line 3 causes compilation to fail.
F. An error at line 4 causes compilation to fail.
答案: C
Question No: 2
Given:
Integer i = new Integer (42);
Long 1 = new Long (42);
Double d = new Double (42.0);
Which two expressions evaluate to True? (Choose Two)
A. (i ==1)
B. (i == d)
C. (d == 1)
D. (i.equals (d))
E. (d.equals (i))
F. (i.equals (42))
答案: D, E
Question No: 3
Exhibit :
1. public class test (
2. private static int j = 0;
3.
4. private static boolean methodB(int k) (
5. j += k;
6. return true;
6. )
7.
8. public static void methodA(int i) {
9. boolean b:
10. b = i 10 | methodB (4);
11. b = i 10 || methodB (8);
12. }
13.
14. public static void main (String args[] ) (
15. methodA (0);
16. system.out.printIn(j);
17. )
18. )
What is the result?
A. The program prints “0”
B. The program prints “4”
C. The program prints “8”
D. The program prints “12”
E. The code does not complete.
答案: B
Question No: 4
Given
1. Public class test (
2. Public static void main (String args[]) (
3. System.out.printIn (6 ^ 3);
4. )
5. )
What is the output?
答案: 5
Question No: 5
Given:
1. public class Foo {
2. public static void main (String [] args) {
3. StringBuffer a = new StringBuffer (“A”);
4. StringBuffer b = new StringBuffer (“B”);
5. operate (a,b);
6. system.out.printIn{a + “,” +b};
7. }
8. static void operate (StringBuffer x, StringBuffer y) {
9. x.append {y};
10. y = x;
11. }
12. }
What is the result?
A. The code compiles and prints “A,B”.
B. The code compiles and prints “A,A”.
C. The code compiles and prints “B,B”.
D. The code compiles and prints “AB,B”.
E. The code compiles and prints “AB,AB”.
F. The code does not compile because “+” cannot be overloaded for StringBuffer.
答案: D
Question No: 6
Exhibit:
1. Public class test (
2. Public static void stringReplace (String text) (
3. Text = text.replace (‘j’ , ‘i’);
4. )
5.
6. public static void bufferReplace (StringBuffer text) (
7. text = text.append (“C”)
8. )
9.
10. public static void main (String args[]) (
11. String textString = new String (“java”);
12. StringBuffer text BufferString = new StringBuffer (“java”);
13.
14. stringReplace (textString);
15. BufferReplace (textBuffer);
16.
17. System.out.printIn (textString + textBuffer);
18. )
19. )
What is the output?
答案: JAVAJAVA
Question No: 7
Exhibit:
1. public class test {
2. public static void add3 (Integer i) }
3. int val = i.intValue ( );
4. val += 3;
5. i = new Integer (val);
6. )
7.
8. public static void main (String args [ ] ) {
9. Integer i = new Integer (0);
10. add3 (i);
11. system.out.printIn (i.intValue ( ) );
12. }
13. )
What is the result?
A. Compilation will fail.
B. The program prints “0”.
C. The program prints “3”.
D. Compilation will succeed but an exception will be thrown at line 3.
答案: B
Question No: 8
Given:
1. public class ConstOver {
2. public ConstOver (int x, int y, int z) {
3. }
4. }
Which two overload the ConstOver constructor? (Choose Two)
A. ConstOver ( ) { }
B. Protected int ConstOver ( ) { }
C. Private ConstOver (int z, int y, byte x) { }
D. Public Object ConstOver (int x, int y, int z) { }
E. Public void ConstOver (byte x, byte y, byte z) { }
答案: A, C
Question No: 9
Given:
1. public class MethodOver {
2. public void setVar (int a, int b, float c) {
3. }
4. }
Which two overload the setVar method? (Choose Two)
A. Private void setVar (int a, float c, int b) { }
B. Protected void setVar (int a, int b, float c) { }
C. Public int setVar (int a, float c, int b) (return a;)
D. Public int setVar (int a, int b, float c) (return a;)
E. Protected float setVar (int a, int b, float c) (return c;)
答案: A, C
Question No: 10
Given:
1. class BaseClass {
2. Private float x = 1.0f ;
3. protected float getVar ( ) ( return x;)
4. }
5. class Subclass extends BaseClass (
6. private float x = 2.0f;
7. //insert code here
8. )
Which two are valid examples of method overriding? (Choose Two)
A. Float getVar ( ) { return x;}
B. Public float getVar ( ) { return x;}
C. Float double getVar ( ) { return x;}
D. Public float getVar ( ) { return x;}
E. Public float getVar (float f ) { return f;}
答案: B, D
Question No: 11
Which two demonstrate an “is a” relationship? (Choose Two)
A. public interface Person { }
public class Employee extends Person { }
B. public interface Shape { }
public class Employee extends Shape { }
C. public interface Color { }
public class Employee extends Color { }
D. public class Species { }
public class Animal (private Species species;)
E. interface Component { }
Class Container implements Component (
Private Component[ ] children;
)
答案: D, E
Question No: 12
Which statement is true?
A. An anonymous inner class may be declared as final.
B. An anonymous inner class can be declared as private.
C. An anonymous inner class can implement multiple interfaces.
D. An anonymous inner class can access final variables in any enclosing scope.
E. Construction of an instance of a static inner class requires an instance of the enclosing outer class.
答案: D
Question No 13
Given:
1. package foo;
2.
3. public class Outer (
4. public static class Inner (
5. )
6. )
Which statement is true?
A. An instance of the Inner class can be constructed with “new Outer.Inner ()”
B. An instance of the inner class cannot be constructed outside of package foo.
C. An instance of the inner class can only be constructed from within the outer class.
D. From within the package bar, an instance of the inner class can be constructed with “new inner()”
答案: A
Question No 14
Exhibit:
1. public class enclosingone (
2. public class insideone{}
3. )
4. public class inertest(
5. public static void main (string[]args)(
6. enclosingone eo= new enclosingone ();
7. //insert code here
8. )
9. )
Which statement at line 7 constructs an instance of the inner class?
A. InsideOnew ei= eo.new InsideOn();
B. Eo.InsideOne ei = eo.new InsideOne();
C. InsideOne ei = EnclosingOne.new InsideOne();
D. EnclosingOne.InsideOne ei = eo.new InsideOne();
答案: D
Question No 15
Exhibit:
1. interface foo {
2. int k = 0;
3. }
4.
5. public class test implements Foo (
6. public static void main(String args[]) (
7. int i;
8. Test test = new test ();
9. i= test.k;
10.i= Test.k;
11.i= Foo.k;
12.)
13.)
14.
What is the result?
A. Compilation succeeds.
B. An error at line 2 causes compilation to fail.
C. An error at line 9 causes compilation to fail.
D. An error at line 10 causes compilation to fail.
E. An error at line 11 causes compilation to fail.
答案: A
Question No 16
Given:
1. //point X
2. public class foo (
3. public static void main (String[]args) throws Exception {
4. printWriter out = new PrintWriter (new
5. java.io.outputStreamWriter (System.out), true;
6. out.printIn(“Hello”);
7. )
8. }
Which statement at PointX on line 1 allows this code to compile and run?
A. Import java.io.PrintWriter;
B. Include java.io.PrintWriter;
C. Import java.io.OutputStreamWriter;
D. Include java.io.OutputStreamWriter;
E. No statement is needed.
答案: A
Question No 17
Which two statements are reserved words in Java? (Choose Two)
A. Run
B. Import
C. Default
D. Implement
答案: B, C
Question No 18
Which three are valid declarations of a float? (Choose Three)
A. Float foo = -1;
B. Float foo = 1.0;
C. Float foo = 42e1;
D. Float foo = 2.02f;
E. Float foo = 3.03d;
F. Float foo = 0x0123;
答案: A, D, F
Question No 19
Leading the way in IT testing and certification tools,
Question No 19
Given:
8. int index = 1;
9. boolean[] test = new Boolean[3];
10. boolean foo= test [index];
What is the result?
A. Foo has the value of 0.
B. Foo has the value of null.
C. Foo has the value of true.
D. Foo has the value of false.
E. An exception is thrown.
F. The code will not compile.
答案: D
Question No 20
Given:
1. public class test(
2. public static void main(string[]args){
3. string foo = args [1];
4. string foo = args [2];
5. string foo = args [3];
6. }
7. )
And command line invocation:
Java Test red green blue
What is the result?
A. Baz has the value of “”
B. Baz has the value of null
C. Baz has the value of “red”
D. Baz has the value of “blue”
E. Bax has the value of “green”
F. The code does not compile.
G. The program throws an exception.
答案: G
Question No 21
Given:
8. int index = 1;
9. int [] foo = new int [3];
10.int bar = foo [index];
11.int baz = bar + index;
What is the result?
A. Baz has the value of 0
B. Baz has the value of 1
C. Baz has the value of 2
D. An exception is thrown.
E. The code will not compile.
答案: B
Question No 22
Given:
1. public class foo {
2. public static void main (String[]args) {
3. String s;
4. system.out.printIn (“s=” + s);
5. }
6. }
What is the result?
A. The code compiles and “s=” is printed.
B. The code compiles and “s=null” is printed.
C. The code does not compile because string s is not initialized.
D. The code does not compile because string s cannot be referenced.
E. The code compiles, but a NullPointerException is thrown when toString is called.
答案: C
Question No 23
Which will declare a method that forces a subclass to implement it?
A. Public double methoda();
B. Static void methoda (double d1) {}
C. Public native double methoda();
D. Abstract public void methoda();
E. Protected void methoda (double d1){}
答案: D
Question No 24
You want subclasses in any package to have access to members of a superclass. Which is the most
restrictive access modifier that will accomplish this objective?
A. Public
B. Private
C. Protected
D. Transient
E. No access modifier is qualified
答案: C
Question No 25
Given:
1. abstract class abstrctIt {
2. abstract float getFloat ();
3. }
4. public class AbstractTest extends AbstractIt {
5. private float f1= 1.0f;
6. private float getFloat () {return f1;}
7. }
What is the result?
A. Compilation is successful.
B. An error on line 6 causes a runtime failure.
C. An error at line 6 causes compilation to fail.
D. An error at line 2 causes compilation to fail.
答案: C
Question No 26
Exhibit:
1. public class test(
2. public int aMethod()[
3. static int i=0;
4. i++;
5. return I;
6. ]
7. public static void main (String args[]){
8. test test = new test();
9. test.aMethod();
10.int j = test.aMethod();
11.System.out.printIn(j);
12.}
13.)
What is the result?
A. Compilation will fail.
B. Compilation will succeed and the program will print “0”
C. Compilation will succeed and the program will print “1”
D. Compilation will succeed and the program will print “2”
答案: D
Question No 27
Given:
1. class super {
2. public float getNum() {return 3.0f;}
3. }
4.
5. public class Sub extends Super {
6.
7. }
Which method, placed at line 6, will cause a compiler error?
A. Public float getNum() {return 4.0f; }
B. Public void getNum () { }
C. Public void getNum (double d) { }
D. Public double getNum (float d) {retrun 4.0f; }
答案: B
Question No 28
Which declaration prevents creating a subclass of an outer class?
A. Static class FooBar{}
B. Private class FooBar{}
C. Abstract public class FooBar{}
D. Final public class FooBar{}
E. Final abstract class FooBar{}
答案: D
Question No 29
Given:
1. byte [] arry1, array2[];
2. byte array3 [][];
3. byte[][] array4;
If each array has been initialized, which statement will cause a compiler error?
A. Array2 = array1;
B. Array2 = array3;
C. Array2 = array4;
D. Both A and B
E. Both A and C
F. Both B and C
答案: F
Question No 30
Exhibit:
1. class super (
2. public int I = 0;
3.
4. public super (string text) (
5. I = 1
6. )
7. )
8.
9. public class sub extends super (
10. public sub (string text) (
11. i= 2
12. )
13.
14. public static void main (straing args[]) (
15. sub sub = new sub (“Hello”);
16. system.out. PrintIn(sub.i);
17. )
18. )
What is the result?
A. Compilation will fail.
B. Compilation will succeed and the program will print “0”
C. Compilation will succeed and the program will print “1”
D. Compilation will succeed and the program will print “2”
答案: A
Question No 31
Given:
1. public class returnIt (
2. returnType methodA(byte x, double y) (
3. return (short) x/y * 2;
4. )
5. )
What is the valid returnType for methodA in line 2?
A. Int
B. Byte
C. Long
D. Short
E. Float
F. Double
答案: F
Question No 32
Given the ActionEvent, which method allows you to identify the affected component?
A. GetClass.
B. GetTarget.
C. GetSource.
D. GetComponent.
E. GetTargetComponent.
答案: C
Question No 33
Which is a method of the MouseMotionListener interface?
A. Public void mouseMoved(MouseEvent)
B. Public boolean mouseMoved(MouseEvent)
C. Public void mouseMoved(MouseMotionEvent)
D. Public boolean MouseMoved(MouseMotionEvent)
E. Public boolean mouseMoved(MouseMotionEvent)
答案: A
有一道 java面向对象编程题 求大家帮我写一下 面向对象基础 看到迷茫
package employee;
public class Employee {
//员工私有属性
private String name; //员工姓名
private int age; //员工年龄
private String position; //员工职位
private int salary; //工资
/**
* 给所有的属性指定初始值
* @param name
* @param age
* @param position
* @param salary
*/
public Employee(String name,int age,String position,int salary){
this.name = name;
this.age =age;
this.position = position;
this.salary = salary;
}
/**
* 给name属性赋值
* @param name
*/
public void setName(String name){
this.name = name;
}
public String getName() {
return name;
}
/**
* 给age属性赋值
* @param age
*/
public void setAge(int age){
if(age18){
this.age=18;
System.out.println("当年龄无效时，默认为18");
}else{
this.age =age;
}
}
public int getAge() {
return age;
}
/**
* 给position属性赋值
* @param position
*/
public void setPosition(String position){
if(position.equals("售后服务") || position.equals("销售员") ){
this.position = position;
}else{
this.position = "售后服务";
System.out.println("输入不符合要求，默认为售后服务");
}
}
public String getPosition() {
return position;
}
/**
* 给员工工资赋值
* @param salary
*/
public void setSalary(){
if(age=18 age=20){
this.salary = 1000;
}else if(age=21 age=25){
this.salary = 1500;
}else if(age=26 age=30){
this.salary = 2000;
}else if(age=31 age=40){
this.salary = 3000;
}else if(age=41 age=50){
this.salary = 3500;
}else if(age=51){
this.salary = 4000;
}else{
System.out.println("没有设置年龄或者年龄无效");
}
}
public int getSalary() {
return salary;
}
}
测试类
package employee;
import java.util.Scanner;
public class TestEmployee {
public static void main(String[] args){
Employee emp1 = new Employee(null, 0, null, 0) ;
Scanner sc = new Scanner(System.in);
System.out.println("请输入第一个员工姓名");
//获取输入的名字
String name1 = sc.next();
emp1.setName(name1);
System.out.println("请输入第一个员工年龄");
//获取输入的年龄
int age1 = sc.nextInt();
emp1.setAge(age1);
System.out.println("请输入第一个员工职位");
//获取输入的职位
String position1 = sc.next();
emp1.setPosition(position1);
emp1.setSalary();
System.out.println("---------------------------------");
System.out.println("员工1姓名为："+emp1.getName());
System.out.println("年龄："+emp1.getAge());
System.out.println("工作为："+emp1.getPosition());
System.out.println("工资为："+emp1.getSalary());
}
}
第一次回答问题，玩玩而已但是还是希望采纳
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发布于：2022-11-26，除非注明，否则均为原创文章，转载请注明出处。