Chapter 3

Question 1

What is an algorithm?

Answer 1

A finite set of step-by-step instructions that specifies a process of moving from the initial situation to the final situation.

Question 2

What 5 things make up a good algorithm?

Answer 2

1) Correct
2) Easy to read and understand
3) Easy to debug
4) Easy to modify to solve variations of the original task
5) Efficient

Question 3

Define stepwise refinement

Answer 3

It is a method of constructing algorithms that decomposes a complex algorithm into smaller, simpler algorithms.

Question 4

Programs using stepwise refinement are:

Answer 4

1) Easy to understand
2) Free of errors
3) Easy to test and debug
4) Easy to modify
5) Imposes a structure on the problem
6) Can think at a higher level of abstraction.

Question 5

Define Pseudocode

Answer 5

Combies naturalness of natural language with the structure of a programming language

Question 6

What 4 benefits do we get from using pseudocode

Answer 6

1) Helps us think more abstractly
2) Allows us to trace our programs very early in development
3) Can provide a common language on a developement team
4) Can be implemented in a variety of programming languages

Question 7

4 Types of accesor methods + description

Answer 7

1) Public - any method can access from any class
2) Protected - can be called from any method from the same class or sublcass
3) Private - May be only called withing the same class
4) Package - may be called from the same package

Question 8

What is a helper method?

Answer 8

Small methods that are created to help and reduce code in another method. They can be called patterns.

Question 9

What is a stub?

Answer 9

A method that has just enough code to compile but not actually to do its job.

Question 10

What are 3 benefits of a stub?

Answer 10

1) They serve as placeholders for work that still must be completed
2) Allows the code to compile even though its not finished.
3) A compiled program can run with may allow some early testing to be performed

Question 11

Define top-down design

Answer 11

Another name for stepwise refinement, you start at the top method and work down to all the helper methods.

Question 12

What 3 things make a program easy to understand?

Answer 12

1) Each method including the main method is composed of a few easily understoo statments.
2) Each method has a single, well defined purpose
3) Each method can be understood by examining the statements it contains