Function encapsulation in java

[Java]
// Triangle class, used to encapsulate attributes and functions of a Triangle.
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 =;
This. sideB = B;
This. sideC = c;
// Parameters a, B, and c are assigned to sideA, sideB, and sideC respectively.
If (this. sideA + this. sideB> this. sideC & this. sideA + this. sideC> this. sideB & this. sideB + this. sideC> this. sideA) // a, B, and c constitute the conditional expression of the triangle.
{
This. boo = true; // assign a value to boo.
}
Else
{
This. boo = false; // assign a value to boo.
}
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 ("not a triangle, perimeter cannot be calculated ");
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 ("not a triangle, cannot calculate area ");
Return 0;
}
}
Public void setABC (double a, double B, double c)
{
This. sideA =;
This. sideB = B;
This. sideC = c; // parameters a, B, and c are assigned to sideA, sideB, and sideC respectively.
If (this. sideA + this. sideB> this. sideC & this. sideA + this. sideC> this. sideB & this. sideB + this. sideC> this. sideA) // a, B, and c constitute the conditional expression of the triangle.
{
This. boo = true; // assign a value to boo.
}
Else
{
This. boo = false; // assign a value to boo.
}
}
 
}

 

[Java]
// Lader class, used to encapsulate Lader attributes and functions.
 
Package qing;
 
Public class Lader {
Double above, bottom, height, area;
Lader (double a, double B, double h)
{
This. above =;
This. bottom = B;
This. height = h; // method body. Assign the parameters a, B, and c to the values above, bottom, and height respectively.
}
Public double getArea ()
{
This. area = (this. above + this. bottom) * this. height/2; // method body, which must be calculated and returned by area
Return this. area;
}
 
}

 

[Java]
// Circle class, used to encapsulate attributes and functions of Circle.
 
Package qing;
 
Public class Circle {
Double radius, area;
Circle (double r)
{
This. radius = r; // method body
}
Public double getArea () // code of the getArea method body
{
This. area = Math. PI * this. radius * this. radius; // method body, which must be calculated and returned by area
Return this. area;
}
Public double getLength ()
{
Double length;
Length = 2 * Math. PI * this. radius; // The length is calculated and returned.
Return length;
}
Void setRadius (double newRadius)
{
Radius = newRadius;
}
Double getRadius ()
{
Return radius;
}
 
}

 

[Java]
// Test class, used to Test whether the functions of each class can be implemented.
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); // create an object circle
Trangle = new Triangle (); // creates the trangle object.
Lader = new Lader (3, 4, 5); // create an object lader
Length = circle. getLength (); // the circumference of the method called by circle is returned and assigned to length.
System. out. println ("circle perimeter:" + length );
Area = circle. getArea (); // The area returned by the method called by circle and assigned to area
System. out. println ("area of the circle:" + area );
Length = trangle. getLength (); // call the trangle method to return the perimeter and assign it to length.
System. out. println ("Triangle perimeter:" + length );
Area = trangle. getArea (); // call the trangle method to return the area and assign it to the area
System. out. println ("Triangle area:" + area );
Area = lader. getArea (); // lader calls the method to return the area and assigns it to area
System. out. println ("Trapezoid area:" + area );
Trangle. setABC (12, 34, 1); // set three edges in the trangle call method. You must change the three edges to 12, 34, and 1.
Area = trangle. getArea (); // call the trangle method to return the area and assign it to the area
System. out. println ("Triangle area:" + area );
Length = trangle. getLength (); // call the trangle method to return the perimeter and assign it to length.
System. out. println ("Triangle perimeter:" + length );
}
 
}