[java]
//Triangle类，用于封装Triangle的属性及功能。
package qing;
public class Triangle {
double sideA,sideB,sideC,area,length;
boolean boo;
Triangle ()
{
this.sideA = 3;
this.sideB = 4;
this.sideC = 5;
}
public boolean Trangle(double a,double b,double c)
{
this.sideA = a;
this.sideB = b;
this.sideC = c;
//参数a,b,c分别赋值给sideA,sideB,sideC
if(this.sideA + this.sideB > this.sideC ;; this.sideA + this.sideC > this.sideB ;; this.sideB + this.sideC > this.sideA) //a,b,c构成三角形的条件表达式
{
this.boo = true;//给boo赋值。
}
else
{
this.boo = false;//给boo赋值。
}
return boo;
}
public double getLength()
{
if(this.sideA + this.sideB > this.sideC ;; this.sideA + this.sideC > this.sideB ;; this.sideB + this.sideC > this.sideA)
{
this.length = this.sideA + this.sideB + this.sideC;
}
else
{
System.out.println("不是一个三角形,不能计算周长");
this.length = 0;
}
return this.length;
}
public double getArea()
{
if(this.sideA + this.sideB > this.sideC ;; this.sideA + this.sideC > this.sideB ;; this.sideB + this.sideC > this.sideA)
{
double p=(sideA+sideB+sideC)/2.0;
area=Math.sqrt(p*(p-sideA)*(p-sideB)*(p-sideC)) ;
return area;
}
else
{
System.out.println("不是一个三角形,不能计算面积");
return 0;
}
}
public void setABC(double a,double b,double c)
{
this.sideA = a;
this.sideB = b;
this.sideC = c;//参数a,b,c分别赋值给sideA,sideB,sideC
if(this.sideA + this.sideB > this.sideC ;; this.sideA + this.sideC > this.sideB ;; this.sideB + this.sideC > this.sideA) //a,b,c构成三角形的条件表达式
{
this.boo = true;//给boo赋值。
}
else
{
this.boo = false;//给boo赋值。
}
}
}
[java]
//Lader类，用于封装Lader的属性及功能。
package qing;
public class Lader {
double above,bottom,height,area;
Lader(double a,double b,double h)
{
this.above = a;
this.bottom = b;
this.height = h;//方法体，将参数a,b,c分别赋值给above,bottom,height
}
public double getArea()
{
this.area = (this.above + this.bottom) * this.height/2;//方法体，,要求计算出area返回
return this.area;
}
}
[java]
//Circle类，用于封装Circle的属性及功能。
package qing;
public class Circle {
double radius,area;
Circle(double r)
{
this.radius = r; //方法体
}
public double getArea() //getArea方法体的代码
{
this.area = Math.PI * this.radius * this.radius; //方法体，要求计算出area返回
return this.area;
}
public double getLength()
{
double length;
length = 2 * Math.PI * this.radius;//要求计算出length返回
return length;
}
void setRadius(double newRadius)
{
radius=newRadius;
}
double getRadius()
{
return radius;
}
}
[java]
//Test类，用于测试各个类内的功能是否能实现。
package qing;
public class Test {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
double length,area;
Circle circle=null;
Triangle trangle;
Lader lader;
circle = new Circle(3); //创建对象circle
trangle = new Triangle (); //创建对象trangle。
lader = new Lader(3,4,5); //创建对象lader
length = circle.getLength(); // circle调用方法返回周长并赋值给length
System.out.println("圆的周长:"+length);
area = circle.getArea(); // circle调用方法返回面积并赋值给area
System.out.println("圆的面积:"+area);
length = trangle.getLength(); // trangle调用方法返回周长并赋值给length
System.out.println("三角形的周长:"+length);
area = trangle.getArea();// trangle调用方法返回面积并赋值给area
System.out.println("三角形的面积:"+area);
area = lader.getArea() ; // lader调用方法返回面积并赋值给area
System.out.println("梯形的面积:"+area);
trangle.setABC(12, 34, 1); // trangle调用方法设置三个边，要求将三个边修改为12,34,1。
area = trangle.getArea();// trangle调用方法返回面积并赋值给area
System.out.println("三角形的面积:"+area);
length = trangle.getLength(); // trangle调用方法返回周长并赋值给length
System.out.println("三角形的周长:"+length);
}
