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

Chapter 5 Methods

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

Introduction to Methods

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?

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

Developing a program that finds the roots of a quadratic equation

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

Discriminants vs Parabola Types Quadratic Formula Discriminants vs Parabola Types

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

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

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!

That’s the End of Chapter 5

Any Questions?