Methods are commonly used to break a problem down into small manageable pieces. A large task can be broken down into smaller tasks (methods) that contain the details of how to complete that small task. The larger problem is then solved by implementing the smaller tasks (calling the methods) in the correct order.

This also allows for efficiencies, since the method can be called as many times as needed without rewriting the code each time.

Task -1 void Methods

1. Copy the file Geometry.java (code listing 5.1) from the Student CD or as directed by your instructor. This program will compile, but when you run it, it doesn't appear to do anything except wait. That is because it is waiting for user input, but the user doesn't have the menu to choose from yet. We will need to create this.

2. Above the main method, but in the Geometry class, create a static method called printMenu that has no parameter list and does not return a value. It will simply print out instructions for the user with a menu of options for the user to choose from. The menu should appear to the user as:

This is a geometry calculator

Choose what you would like to calculate

1. Find the area of a circle

2. Find the area of a rectangle

3. Find the area of a triangle

4. Find the circumference of a circle

5. Find the perimeter of a rectangle

6. Find the perimeter of a triangle

Enter the number of your choice:

3. Add a line in the main method that calls the printMenu method as indicated by the comments.

4. Compile, debug, and run. You should be able to choose any option, but you will always get 0 for the answer. We will fix this in the next task.

Task -2

Value-Returning Methods

1. Write a static method called circleArea that takes in the radius of the circle and returns the area using the formula A = Πr².

2. Write a static method called rectangleArea that takes in the length and width of the rectangle and returns the area using the formula A = lw.

3. Write a static method called triangleArea that takes in the base and height of the triangle and returns the area using the formula A = ½bh.

4. Write a static method called circleCircumference that takes in the radius of the circle and returns the circumference using the formula C = 2πr.

5. Write a static method called rectanglePerimeter that takes in the length and the width of the rectangle and returns the perimeter of the rectangle using the formula P = 2l +2w.

6. Write a static method called trianglePerimeter that takes in the lengths of the three sides of the triangle and returns the perimeter of the triangle which is calculated by adding up the three sides.

Task -3

Calling Methods

1. Add lines in the main method in the GeometryDemo class which will call these methods. The comments indicate where to place the method calls.

2. Below, write some sample data and hand calculated results for you to test all 6 menu items.

3. Compile, debug, and run. Test out the program using your sample data.