java 5-1 （封装一类图形对象。求图形的面积。周长。）

//三角形

public class  Triangle
{
public static void main(String[] args)
{
CTriangle c = new CTriangle(3,4,5);
System.out.println("三角形的面积是："+c.area()+"    三角形的周长是: "+c.perimeter());

}
}

class CTriangle{

float  x,y,z,p,are,per;
CTriangle(float x, float y, float z)
{
this.x = x;
this.y = y;
this.z = z;
}

public void set_x(int x)
{
this.x = x;
}

public void set_y(int y)
{
this.y = y;
}

public void set_z(int z)
{
this.z = z;
}

public float area()//计算面积
{
p = (x + y + z) / 2.0f;
are = (float)Math.sqrt(p * (p - x) * (p - y) * (p - z));
return are;
}

public float perimeter()//求周长
{
return (per = x + y + z);
}
}

public class  Circular
{
public static void main(String[] args)
{
CCircular c = new CCircular(5);
System.out.println("圆的面积是："+c.area()+"    圆的周长是: "+c.perimeter());
}
}

class CCircular
{

float r;//这是圆的半径

CCircular(float r)
{
this.r = r;
}

public void set_r(float r)
{
this.r = r;
}

public float area()//计算面积
{

return (r* 3.14f * r );
}

public float perimeter()//求周长
{
return (2.0f * 3.14f * r);
}

}