Exam 1 Topics
CS141: Introduction to Programming, Fall 2011

General Comments and Recommendations

• The exam will cover Chapters 1-4 of the text.
• 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 (answers are in the text)
  • Review the reading quizzes
  • Review the programming code-completion and programming exercises.
  • Be able to do the loops described in this exercise.

Chapter 1: Introduction

• Java sytax for creating a class, e.g. see HelloPrinter on p. 13
• 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
  • braces are on lines by themselves
  • matching braces a lined up vertically with each other
  • blocks of code are indented
• Compile vs Run-time Errors

Chapter 2: Fundamental Data Types

• Variables
  • What is a variable?
  • Data types - short, int, long, float, boolean, string, etc. What is the difference between float and double or short and int?
  • How is a variable declared? How many times can one declare a given variable?
  • How is a variable initialized? How many times can one set the value of a given variable?
• How does the assignment statement work?
• Java syntax for arithmetic.
• Precedence of arithmetic operations.
• Integer division and remainder (mod function)
• Casting, e.g. forcing a float into an int
• Strings
• String methods (e.g. length, charAt, substring) and sytax for calling them, StringName.methodName(inputs_to_method). See p. 65-66
• String concatentation and escape sequences
• Math methods (e.g. min, max, pow, sqrt)

Chapter 3: Decisions

• Boolean variables and values.
• What is a conditional expression?
• Comparisons: Relational operators, e.g. <, >, <=, >=, ==, !=
• Beware: relational operators are binary. For example, (2 < x < 5) is not a legal java expression.
• Beware: the == operator should not be used with Strings
• if statements, if-else statements (p. 80)
• Multiway if-else
• Nested if, if-else statements - line up brackets so the structure is clear!
• Beware of where you put semicolons!
• Switch statement
• Lexicographic ordering of Strings using the compareTo() method.
• Combining boolean expressions with AND (&&), OR (||), NOT (!)

Chapter 4: Loops

• Components of a loop
  • Identify the loop variable (or whatever is controlling the loop)
  • Controlling the loop - initializing the loop, loop condition, loop update
  • What is the loop body?
• Types of loops:
  • while loop
  • for-loop
  • do-while loop
• When is each type of loop used?
• What is a sentinel?
• What does it mean to trace or unravel a loop?
• 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)
  • Prompting for correct type of input from user
  • loop exercise