1.類的成員變量猜數字游戲一個類A有一個成員變量v有一個初值100。定義一個類對A類的成員變量v進行猜。如果大了則提示大了小了則提示小了。等于則提示猜測成功。

import?java.util.*;public?class?lianxi{
????public?static?void?main(String[]?dsa)
????{
????A?a=new?A();
????Scanner?input=new?Scanner(System.in);
????while?(1==1)
????{
????????System.out.println("請猜測數字");
????????int?i=input.nextInt();
????????if?(ia.v)
????????{
????????????System.out.println("大了");
????????????continue;
????????}
????????else
????????{
????????????System.out.println("恭喜你猜對了！");
????????????break;
????????}
????}
????}}class?A{
????public?int?v=100;}

2.類的成員變量請定義一個交通工具(Vehicle)的類其中有:屬性速度(speed)體積(size)等等方法移動(move())設置速度(setSpeed(int speed))加速speedUp(),減速speedDown()等等.最后在測試類Vehicle中的main()中實例化一個交通工具對象并通過方法給它初始化speed,size的值并且通過打印出來。另外調用加速減速的方法對速度進行改變。

public?class?Vehicle{
????private?int?speed;
????private?String?size;
????public?void?move()
????{
????System.out.println("i'm?moving");
????}
????public?void?setSpeed(int?speed)
????{
????????System.out.println("now?i'm?running?with"+speed+"per?hour");
????}
????public?void?speedUp()
????{
????????Vehicle?v=new?Vehicle();
????????v.setSpeed(1000);
????}
????public?void?speedDown()
????{
????Vehicle?v=new?Vehicle();
????????v.setSpeed(20);
????}
????public?static?void?main(String[]?dsa)
????{
????Vehicle?v=new?Vehicle();
????v.speed=100;
????v.size="50/m^3";
????System.out.println("the?initial?speed?is"+v.speed+"and?my?size?is?"+v.size);
????v.speedUp();
????v.speedDown();
????}}

3.類的成員變量與方法、構造方法在程序中經常要對時間進行操作但是并沒有時間類型的數據。那么我們可以自己實現一個時間類來滿足程序中的需要。定義名為MyTime的類其中應有三個整型成員時hour分minute秒second為了保證數據的安全性這三個成員變量應聲明為私有。為MyTime類定義構造方法以方便創建對象時初始化成員變量。再定義diaplay方法用于將時間信息打印出來。為MyTime類添加以下方法addSecond(int sec)addMinute(int min)addHour(int hou)subSecond(int sec)subMinute(int min)subHour(int hou)分別對時、分、秒進行加減運算。

public?class?MyTime{
????private?int?hour;
????private?int?minute;
????private?int?second;
????public?MyTime(int?x,int?y,int?z)
????{
????this.hour=x;
????this.minute=y;
????this.second=z;
????}
????public?void?display()
????{
????System.out.println("the?time?is?"+this.hour+":"+this.minute+":"+this.second);
????}
????public?void?addHour(int?hou)
????{
????this.hour=this.hour+hou;
????}
????public?void?addSecond(int?sec)
????{
????this.second=this.second+sec;
????}
????public?void?addMinute(int?min)
????{
????this.minute=this.minute+min;
????}
????public?void?subHour(int?hou)
????{
????this.hour=this.hour-hou;
????}
????public?void?subMinute(int?min)
????{
????this.minute=this.minute-min;
????}
????public?void?subSecond(int?sec)
????{
????this.second=this.second-sec;
????}}

04.構造方法 編寫Java程序模擬簡單的計算器。 定義名為Number的類其中有兩個整型數據成員n1和n2應聲明為私有。編寫構造方法賦予n1和n2初始值再為該類定義加addition、減subtration、乘multiplication、除division等公有成員方法分別對兩個成員變量執行加、減、乘、除的運算。 在main方法中創建Number類的對象調用各個方法并顯示計算結果。

public?class?Number{
????private?int?x;
????private?int?y;
????public?Number(int?x,int?y)
????{
????this.x=x;
????this.y=y;
????}
????public?void?plus()
????{
????System.out.println("the?result?is:"+(this.x+this.y));
????}
????public?void?except()
????{
????System.out.println("the?result?is?:"+(this.x-this.y));
????}
????public?void?multiplication()
????{
????System.out.println("the?result?is?:"+(this.x*this.y));
????}
????public?void?division()
????{
????System.out.println("the?result?is?:"+(this.x/this.y));
????}
????public?static?void?main(String[]?dsa)
????{
????Number?lian=new?Number(4,4);
????lian.plus();
????lian.except();
????lian.multiplication();
????lian.division();
????}}

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