1. CS-0401
INTERMEDIATE PROGRAMMING USING JAVA
Prof. Dr. Paulo Brasko Ferreira
Fall 2014

2. Chapter 5 Methods

3. Chapter 5 Presentation Outline
Introduction to Methods
Passing Arguments to a Method
More About Local Variables
Returning a Value from a Method
Problem Solving with Methods
This class will be mostly hands on, using NetBeans and the PC projector

4. Introduction to Methods

5. Introduction to Methods
What is best for my company?
Having a single person to handle all the tasks?
Having a team of specialized persons in each area?

6. Introduction to Methods
What is best for my program?
To have a single main() method that handles all code tasks
To have many methods, each one handling a specific code task

7. Developing a program that finds the roots of a quadratic equation

8. Quadratic Equation Solver
Requirements:
Input: - via command line (e.g., “java myProgram 2 3 4”)
- user must provide three real numbers a, b, and c
Output: - the roots of the about equation, i.e., the
values of x that makes the above equation
equals to zero

9. Discriminants vs Parabola Types
Quadratic Formula
Discriminants vs Parabola Types

10. Implementing the code
QuadraticEquationSolver: all functionality inside the main() method
QuadraticEquationSolver2: splitting the functionality in many methods, which are called by the main() method

11. Main Points to Talk About
Method names (e.g., calculateTaxes())
Method modifiers (e.g., private static)
Private, public, protected, static, final
Method input arguments
Void, list of arguments
Method returning values
Void, a single output type
Calling methods
With and without input arguments (primitive data are passed by value; objects are passed by reference)
With and without returning type
Documenting methods
Variable scopes
Throwing Exceptions

12. That’s an order Soldier!
Essential Reading
It is essential for you to read the supplemental power point presentation called
CSO_Gaddis_Java_Chapter5.ppt
That’s an order Soldier!

13. That’s the End of Chapter 5

14. Any Questions?