Exam 1 Topics
CS141: Introduction to Programming, Fall 2015

General Comments and Recommendations

The exam will cover Chapters 1-5 of the text (excluding 5.10).
The exam will be 1 hour long. It will be closed book. Electronic devices, of any kind, will not be allowed.
It is strongly recommended that students:
- Re-read the text.
- Do the self-check exercises in each chapter.
- Review the reading quizzes.
- Review the lab assignments.
Practice Problems which could appear on the exam:
- Variables (pdf)
- Basic Looping Problems (pdf). Solutions are here, but try to do them on your own first.
- Scope (pdf), Solutions are here.
- Nested Loop Problems (pdf)
- Practice Boolean Operators (pdf) (with solutions)
- Old exams.
- Netbeans Project for the game of chance (Player, Game, Die classes)

Chapter 1: Introduction

Vocabulary

syntax
operators
punctuation
key words
programmer defined names
variables
statement
expression
Java compiler
byte code
source file
Java Virtual Machine
IDE - Integrated Development Enviroment (e.g Netbeans)

Topics

Java sytax for creating a class.
What is a statement?
How is a block of code specified (i.e. with braces)?
Name of java file must be same as the java class.
Printing output using System.out.println()
Programming Conventions (Style guide):
- files names begin with uppercase
- method (function) names begin with lowercase
- Blocks of code are indented, i.e. Code within braces is indented.
What are compile vs run-time errors?

Chapter 2: Fundamental Data Types

Vocabulary

Class and Method Syntax:
  ... class, object, method
  ... class header and body
  ... class name = file name
  ... access specifier
  ... method header and body
  ... parameter & argument
  ... brackets - code blocks
  ... statement vs expression
  ... semicolons and other punctuation {},(),//,;,"",''
  ... programming style, indentation, Netbeans formatting tool
  ... comments, single line, multi-line, Javadoc
  ... API Application Programmer Interface
  ... packages and the import statement
  ... dot notation

Variables:
  ... type: primitive vs Class
  ... primitive data types (int, float, double, boolean, char)
  ... Class types (String)
  ... variable declaration
  ... identifier
  ... variable initialization
  ... case sensitive
  ... literal, String literal
  ... constant (final)
  ... scope
String Variables and Operations:
  ... String Class
  ... String operations
  ... escape sequence and control characters See Table 2-2, p. 42
  ... String concatenation and the + operator

Variable Operations:
  ... assignment operator, assignment statement
  ... operator
  ... binary arithmetic operators: +, -, *, /, %
  ... unary arithmetic operators: -, ++, --
  ... Mod function (%)
  ... integer division
  ... Math class, Math.PI, Math.random()
  ... operator precedence
  ... type conversion, cast operator

Keyboard I/O, input/output:
  ... Scanner class
  ... Dialog Boxes
  ... System.out.print, System.out.println
  ... System.out.printf, format specifier
  ... console
  ... standard output/input

Topics

Sample problems: Variables (pdf)
Variables: What are they, how do you create, name, and initialize them?
How many times can one declare a given variable? How many times can one set the value of a given variable?
Types: What is a data type? Why do we have them? What are examples (int,float, boolean, String, etc.)
When can we convert from one type to another? What is casting?
Java Statements: What is a statement, expression, value?
What is a "literal"?
Assignment statement: What is its syntax?
Doing Arithmetic
- Operators - binary (+, -, /, *, %) , unary (-, ++, --)
- Operator Precedence and when you must use parentheses
- The Math class for functions such as sqrt, pow, etc. -
  Learn to use the javadoc api !
- Conversion between numeric types.
Comments: What are they? Why do we have them? What is their syntax?
Common Pitfalls:
- Forgetting to declare and/or initialize a variable.
- Declaring a variable multiple times.
- Using integer division when you don't mean to.
Problem Solving techniques
- Don't jump into coding too quickly. Understand problem, try example by hand, write pseudocode.
- Stepwise refinement - break problem into a sequence of steps that lead to the full solution. Implement one step at a time, compiling (compile time errors) and testing your code (run time erros)
Strings: What is a string? Look at String API (Javadoc).
String methods (e.g. length, charAt, substring) and sytax for calling them, StringName.methodName(inputs_to_method).
String concatentation and escape sequences
Math methods (e.g. min, max, pow, sqrt)
Primitive types (int, float, etc) vs Object types (String, Scanner, etc):

Chapter 3: Classes and Objects

Vocabulary

Object-oriented programming & Class Structure
  ... Class (user defined type)
  ... Object (instance of class)
  ... primitive type vs class type
  ... Attributes, Fields, or Member variables (data)
  ... Methods (actions)

Method Structure:
  ... access specifier or modifier (e.g. public, private)
  ... method name
  ... method parameters
  ... return type, return value
  ... variable scope: local vs global, shadowing

Class Structure (more detail):
  ... Constructors, default constructor
  ... Public interface
  ... Private implementation, data hiding
  ... Mutator methods (setter)
  ... Accessor methods (getter)
  ... toString method
Object Creation and Use
  ... The keyword: new
  ... Sending a message, calling a method
  ... dot notation
  ... (formal) parameter vs argument (actual parameter)
  ... parameter passing
  ... Null pointer and the Null Pointer Exceptions

Code Design and Development
  ... UML Diagram
  ... API (Application Programmer Interface)
  ... Encapsulation, modularization
  ... stepwise refinement
  ... reusability

Testing and Debugging
  ... debugging & testing
  ... tracing code

Topics

Motivation of Classes and Objects: Organizing and structuring code to promote reusability, readability, and correctness
Encapsulation: Separating the public interface from the private (hidden) implementation
Class vs Object Analogies: script vs actor, cookie recipe vs the cookie itself
Example: Die class
Components of a Class (also see class template):
- Data:
  - Member (instance) variables (also know as Attributes, Fields)
- Actions:
  - Public interface (public methods)
    - Common for most classes:
      - Creation: Constructor
      - Access to data: Mutators and Accessors (also called getters and setters)
      - toString
    - Other Public methods for a specific class (e.g. In the Die class, one might have a roll() method)
  - Private Implementation:
    - Data hiding: data is usually private. Use accessors & mutators instead.
    - private methods - not accesible from outside of the class.
Working with Objects
- Creating an object using the keyword new and a constructor
- The null keyword and Null Pointer Exceptions
- Sending an object a message using the public interface. (i.e. calling a method)
- Self referencing using the keyword this
See list of common errors on p. 183 of your text.

Chapter 4: Decision Structures

Vocabulary

Types of Decision Structures:
  ... if statement
  ... if-else statement
  ... multi-way if-else
  ... nested if-else
  ... switch statements
  ... indentation conventions
Code blocks & variable scope

Decision Structure Syntax:
  ... decision logic and flow charts
  ... condition and body
  ... boolean value, expression

Random numbers

Building Boolean Expressions:
  ... relational operator (<, >, <=, >=, ==, !=)
  ... boolean (logical) operators (!, &&, ||)
  ... boolean operators precedence (See table)
  ... truth tables (e.g. Tables 4-6,4-7,4-8)
  ... De Morgan's Laws

String Comparison
  ... Lexicographic ordering (of Strings)
  ... compareTo() and .equals operators

Other (optional)
  ... The Conditional Operator bool ? val1 : val2
  ... Switch statement (p. 238)
  ... DecimalFormat (p. 248)

Topics

if-statement, if-else-statement
- Syntax
- Braces & indentation
- Boolean values and variables:
  - What is a boolean variable? (boolean, true/false)
  - Relational operators – making number comparisons with <, >, <=. >=, ==, !=
  - Beware: relational operators are binary. For example, (2 < x < 5) is not a legal java expression.
  - What is a conditional expression?
  - Be careful!! Equality of Strings. Do not use ==. Instead, use myString1.equals(myString2)
Multiway if-else
Nested if, if-else statements - line up brackets so the structure is clear!
Beware of where you put semicolons!
Combining boolean expressions with AND (&&), OR (||), NOT (!) Write out truth tables.
- Combining with relational operators
- Practice Boolean Operators
Strings and lexicographic ordering – compareTo operator
Rules of Thumb & Common Errors:
- Avoid duplication in branches
- Dangling else problem
- Syntax for condition ( 5 < x < 7 ) is NOT allowed! Need to use boolean operators.
De Morgan's Law:
- !(A && B) same as (!A) || (!B)
- !(A || B) same as (!A) && (!B)
Random numbers, e.g. rolling dice or dealing cards.

Chapter 5: Loops

Vocabulary

increment/decrement operators
while-loop (a pretest loop)
for-loop (a pretest loop)
unwinding and hand tracing
do-while-loop (a posttest loop)
nested loop Control variable, initialization, condition, update; loop body
sentinel value
counter, running total
running totals, accumulator
infinite loop

Topics

Sample loop problems: Basic Looping Problems (pdf). Note solutions are here, but try to do them on your own first.
Sample nested loop problems: Nested Loop Problems (pdf)
Components of any loop:
- Loop variable - the variable that controls the looping
- Loop variable initialization - the starting value of the loop variable.
- Loop condition - this must be true for loop to continue
- Loop variable update - how does loop variable change after each loop
- Loop body - sequence of statements that are executed in the loop
Types of loops:
- while-loops - used when the number of repetitions can't be predicted ahead of time (indefinite)
- for-loops - when you know precisely how many times you will loop (definite). Loop variable only defined within loop.
- do-while-loops - checks condition at end; always executes the body at least once
- Nested loops.
Figuring out what is going on - Hand tracing, unraveling the loop
Common Errors: infinite loops, off-by-one
Sentinel values - the user controls when to stop
Common Uses of Loops:
- Entering a sequence of values.
- Counting the number of items entered.
- Accumulating (e.g. summing) values
- Finding certain values (e.g. max or min)
- Checking for correct user input

Exam 1 Topics CS141: Introduction to Programming, Fall 2015

General Comments and Recommendations

Chapter 1: Introduction

Chapter 2: Fundamental Data Types

Chapter 3: Classes and Objects

Chapter 4: Decision Structures

Chapter 5: Loops

Exam 1 Topics
CS141: Introduction to Programming, Fall 2015