java 构造函数 练习题

上一篇 / 下一篇  2015-10-29 17:49:46 / 个人分类:Java

1、:  猜数字游戏:一个类A有一个成员变量v,有一个初值100。定义一个类,对A类的成员变量v进行猜。如果大了则提示大了,小了则提示小了。等于则提示猜测成功。

public class Question1{

int v=100;

Question1(int VB){

if (VB<v)

System.out.println("smaller");

else if (VB>v)

System.out.println("bigger");

else

System.out.println("right");

}

}


public class TestA{

public static void main(String args[]){

Question1 q = new Question1(30);

Question1 q1 = new Question1(120);

Question1 q2 = new Question1(100);;

}

}



  2、  请定义一个交通工具(Vehicle)的类,其中有: 属性:速度(speed),体积(size)等等  方法:移动(move()),设置速度(setSpeed(int speed)),加速speedUp(),减速speedDown()等等.  最后在测试类Vehicle中的main()中实例化一个交通工具对象,并通过构造方法给它初始化speed,size的值,并且通过打印出来。另外,调用加速,减速的方法对速度进行改变。

public class Vehicle{

double speed;

double size;

Vehicle(double speed, double size){

this.speed=speed;

this.size=size;

System.out.println("speed is "+speed);

System.out.println("size is "+size);

}

public void move(){

System.out.println("i am moving");

}

public void setSpeed(double speed){

this.speed=speed;

}

public void speedUp(){

speed = speed + 50;

System.out.println("the speed is turned up to: "+speed);

}

public void speedDown(){

speed = speed-20;

System.out.println("the speed is turned down to: "+speed);

}

public static void main(String args[]){

Vehicle v1 = new Vehicle(58.23,63.23);

v1.move();

v1.setSpeed(100);

v1.speedUp();

v1.speedDown();

}

}


4、  编写Java程序,模拟简单的计算器。  定义名为Number的类,其中有两个整型数据成员n1和n2,应声明为私有。编写构造方法,赋予n1和n2初始值,再为该类定义加(addition)、减(subtration)、乘(multiplication)、除(division)等公有成员方法,分别对两个成员变量执行加、减、乘、除的运算。  在main方法中创建Number类的对象,调用各个方法,并显示计算结果。 


public class Number{

private double n1;

private double n2;

Number(double n1,double n2){

this.n1=n1;

this.n2=n2;

}

public void addition(){

double sum=0;

sum=n1+n2;

System.out.println("n1+n2 = "+sum);

}

public void subtration(){

double sum=0;

sum=n1-n2;

System.out.println("n1-n2 = "+sum);

}

public void multiplication(){

double sum=0;

sum=n1*n2;

System.out.println("n1 * n2 = "+sum);

}

public void division(){

System.out.println("n1 / n2 = "+n1/n2);

}

public static void main(String args[]){

Number number = new Number(500,100);

number.addition();

number.subtration();

number.multiplication();

number.division();

}


}


5:  编写Java程序,用于显示人的姓名和年龄。 定义一个人类(Person),该类中应该有两个私有属性,姓名(name)和年龄(age)。定义构造方法,用来初始化数据成员。再定义显示(display)方法,将姓名和年龄打印出来。

 undefined

在main方法中创建人类的实例,然后将信息显示。 

public class Person1{

private String name;

private int age;

Person1(String name, int age){

this.name=name;

this.age=age;

System.out.println("my name is: "+name);

System.out.println("my age is: "+age);

}

public static void main(String args[]){

Person1 p=  new Person1("Sandy",35);

}

}



6、  为“无名粉店”写一个类:class WuMingFen 要求: 

1.有三个属性:面码:String theMa  粉的分量(两):int quantity         是否带汤:boolean likeSoup 

2.写一个构造方法,以便于简化初始化过程,如:  WuMingFen f1 = new WuMingFen("牛肉",3,true);

3.重载构造方法,使得初始化过程可以多样化:  WuMingFen f2 = new WuMingFen("牛肉",2); 

4.如何使得下列语句构造出来的粉对象是酸辣面码、2两、带汤的?  WuMingFen f3 = new WuMingFen();

 5.写一个普通方法:check(),用于查看粉是否符合要求。即:将对象的三个属性打印在控制台上。 

public class WuMingFen{

String theMa;

int quantity;

boolean likeSoup;

WuMingFen(String theMa,int quantity){

this.theMa=theMa;

this.quantity=quantity;

}

WuMingFen(String theMa,int quantity,boolean likeSoup){

this(theMa,quantity);

this.likeSoup=likeSoup;

}

public void check(){

String y="Yes";

if (!likeSoup)

y="No";

System.out.println("theMa is: "+theMa);

System.out.println("The quantity is: "+quantity);

System.out.println("The likeSoup is: "+y);

}

public static void main(String args[]){

WuMingFen f1 = new WuMingFen("acid and spicy",2,true);

f1.check();

}

} 


 



TAG: java 练习题

 

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