Thread: Write a class encapsulating the concept of a circle: Help Needed

Prompt: Write a class encapsulating the concept of a circle, assuming a circle has the following attributes: a Point representing the center of the circle, and the radius of the circle, and integer. Include a constructor, the accessors and mutators, and methods toString and equals. Also include methods returning the perimeter ( 2 × 𝜋 × 𝑟 ) and area ( 𝜋 × 𝑟^2) of the circle. Write a client (application) class to test all the methods in your class.

I started out trying to thing how to do this and I mapped out a certain idea but do not know how to incorporate the point represent the center of the circle. I am not sure how to proceed further.. Please give me your wise guidance:

 
import java.awt.*;
public class Circle {
 
public static void main(String[] args) {
 
final double PI = 3.14;       
int x,y, radius = 4;
double area;
double perimeter;
 
area = PI * radius * radius;
perimeter = 2 * PI * radius;
 
// Output Results
System.out.println("The area of the circle is " + area );
System.out.println("The perimeter of the circle is " + perimeter );
}
 
    int x, y, radius; 
    public Circle(int x, int y, int radius) {  
    this.x = x;
    this.y = y;
    this.radius = radius;
    } 
}
 
// For some reason this code has problems.
// I tried integrating it into the top code and 
// That failed, not sure why though. 
 
class public Circle(int x, int y, int radius) {
this.x = x;
this.y = y;
this.radius = radius;
}
 
public Circle() {
this.x = 3;
this.y = 3;
this.radius = 6;
}

I do not know what to do. I have viewed tutorials, but that makes it even more confusing.... I hope you can assist me.
Thank you so much for coping with a noob like me.
Thanks.

I do not think I need to know exactly, put pretty close to it.
Yes. "A toString method that prints out the location of the circle (the x, y coordinates of
the Point) and the radius."

 
public class TestCircle { 
 
public static void main(String[] args) {
 
final double PI = 3.14;  
 
int x,y, radius = 4;
 
double area = 24;
 
double perimeter = 30; 
 
area = PI * radius * radius;
perimeter = 2 * PI * radius;
 
// Output Results
System.out.println("The area of the circle is " + area );
System.out.println("The perimeter of the circle is " + perimeter );
}
}
 
public class Circle {
 
int radius;
int x,y;
public Circle( int x, int y, int radius) {
   this.x = 2;
   this.y = 2;   
   this.radius = 4;
 
}
}

Okay I get it now. So the x and y are the coordinates.

"A toString method that prints out the location of the circle (the x, y coordinates of
the Point) and the radius."

I think the requirement wants you to override the toString method of Object
If you are using netbeans or eclipse, just press Ctrl + spacebar and find the toString and click enter.
that will override the toString method and you must return what you want to print out with that Circle class.
If you are not using any IDE, just create a public method named toString that has return type of String

public class TestCircle {

public static void main(String[] args) {

final double PI = 3.14;

int x,y, radius = 4;

double area = 24;

double perimeter = 30;

area = PI * radius * radius;
perimeter = 2 * PI * radius;

// Output Results
System.out.println("The area of the circle is " + area );
System.out.println("The perimeter of the circle is " + perimeter );
}
}

public class Circle {

int radius;
int x,y;
public Circle( int x, int y, int radius) {
this.x = 2;
this.y = 2;
this.radius = 4;

}
}

I guess you have compilation error with your code?
each java file can contain only one public class. except for nested public class.
it would be better if you put your Circle class in another java file.

So I reworked the code and now I think I only have to find a way to integrate the second code into the first code

 
//First Code
 
import java.awt.Point;
 
public class NewClass {
 
public static void main(String[] args) {
 
final double PI = 3.14;  
 
int x = 2;
int y = 2;
int center = 0;
int radius = 4;
 
double area = 24;
 
double perimeter = 30; 
 
area = PI * radius * radius;
perimeter = 2 * PI * radius;
 
 
// Output Results
System.out.println("The area of the circle is " + area );
System.out.println("The perimeter of the circle is " + perimeter );
System.out.println("The Circle Center is 0, Radius is 4, coordinates are (2,2)");
 
}
}
 
// Second Code
 
class Point {
  int x;
  int y;
 
  public Point (int x, int y) {
     this.x = x;
     this.y = y;
  }
  // Getter/Setters and other methods
}
 
public class Circle {
 
  Point center = null;
  int radius = 0;
 
  public Circle(int x, int y, int rad) {
      center = new Point(x, y);
      radius = rad;
  }
}

I need help with these things:

A Circle constructor that takes a Point object and a radius value as parameters.

Accessors and mutators (getters and setters) for the Point object and the radius.

A toString method that prints out the location of the circle (the x, y coordinates of
the Point) and the radius.

An equals method that returns true if two circles have the same Point location
and radius.

An application class that creates at least one instance of a Circle object.

Thanks

class Point {
int x;
int y;

public Point (int x, int y) {
this.x = x;
this.y = y;
}
// Getter/Setters and other methods
}

you already have created your own/customized Point class. So why do you have to import java.awt.Point?

Circle class:
You need to provide getters for Point and radius in your Circle class.

A Circle constructor that takes a Point object and a radius value as parameters.

I think it would be better if the argument of your constructor would be:
public Circle(Point center, int rad)
since that what the requirement says.

Point class
And in your Point class, you need to override the toString method of Object.
just create a method public String toString() in Point class. then return the coordinates
For Example:

public String toString() {
     return "(" + x + ", " + y + ")";
}

and after, try to create Object Point and print it.
For Example:

Point center = new Point(2,3);
System.out.println(center);

the output of the above code will be (2, 3)

final point center = null;

you declared the class Point with uppercase P
java is a case sensitive programming language.
then it should be final Point center not final point center.

center = new Point(2,2); //Cannot assign value to final variable center

because you made it final. just remove the final keyword,

I finalized my code, but I cannot run it, the program says that there is no main class?
"public static void main(int radius, int x, int y) {" I thought that this was my main class....
Do you know what may be causing this?

 
import java.awt.Point;
 
public class Circle {
 
    Point center = null;
    int radius = 4; 
 
public String toString() {
    int x = 2;
    int y = 2;
    return "(" + x + ", " + y + ")";
} 
 
public static void main(int radius, int x, int y) {
 
    final double PI = 3.14;  
    x = 2;
    y = 2;
    Point center = new Point(2,2);
    radius = 4;
 
    double area = 24;
    double perimeter = 30; 
 
    area = PI * radius * radius;
    perimeter = 2 * PI * radius;
 
    System.out.println("Area of the circle is " + area );
    System.out.println("Perimeter of the circle is " + perimeter );
    System.out.println(center);
    System.out.println("The Circle Center:(2,2), Radius: 4,");
 
class Point {
     int x;
     int y;
 
  public Point (final int x, final int y) {
     this.x = x;
     this.y = y;
 
   }
  }
 }
}

Many Thanks.
-Vex

I finalized my code, but I cannot run it, the program says that there is no main class?

sorry for late reply. I don't do anything related to programming during weekends
the reason is you don't have main method in your class.
public static void main(String[] var) is a special method in java. you cannot modify its parameter (except for the variable name of String array)