1. Chapter 5 The if Statement
5/13/2018 9:32 PM
Chapter 5 The if Statement
Conditional control structure, also called a decision structure
Executes a set of statements when a condition is true
The condition is a Boolean expression
For example, the statement if (x == 5) { y = 20; } assigns the value 20 to y only if x is equal to 5.
Refer to page 105 in the text.
© 2007 Lawrenceville Press

2. Chapter 5 Relational Operators
5/13/2018 9:32 PM
Chapter 5 Relational Operators
Operator Meaning
== equal
< less than
<= less than or equal
> greater than
>= greater than or equal
!= not equal
Refer to page 105 in the text.
Relational operators are used to form Boolean expressions. Boolean expressions evaluate to true or false.
© 2007 Lawrenceville Press

3. Chapter 5 The if-else Statement
5/13/2018 9:32 PM
Chapter 5 The if-else Statement
Contains an else clause that is executed when the if condition evaluates to false. For example, the statement if (x == 5) { y = 20; } else { y = 10; } assigns the value 20 to y if x is equal to 5 or the value 10 if x is not equal to 5.
Refer to pages 106 and 107 in the text.
© 2007 Lawrenceville Press

4. Chapter 5 Nested if-else Statements
5/13/2018 9:32 PM
Chapter 5 Nested if-else Statements
Should be indented to make the logic clear.
Nested statement executed only when the branch it is in is executed. For example, the statement if (x == 5) { y = 20; } else { if (x > 5) { y = 10; } else { y = 0; } } evaluates the nested if-else only when x is not equal to 5.
Refer to page 107 in the text.
© 2007 Lawrenceville Press

5. Chapter 5 The if-else if Statement
5/13/2018 9:32 PM
Chapter 5 The if-else if Statement
Used to decide among three or more actions.
Conditions must be properly ordered for the statement to evaluate as expected. For example, the statement if (x < 5) { y = 20; } else if (x < 10) { y = 40; } else if (x < 15) { y = 80; } would give very different results if the conditions were ordered differently.
Refer to page 108 in the text.
© 2007 Lawrenceville Press

6. Chapter 5 The switch Statement
5/13/2018 9:32 PM
Chapter 5 The switch Statement
Used to decide among three or more actions.
Uses an expression that evaluates to an integer.
The break statement moves program execution to the next statement after the switch.
The default code is optional and is executed when none of the previous cases are met: switch (numLegs) { case 2: System.out.println("human"); break; case 4: System.out.println("beast"); break; case 8: System.out.println("insect"); break; default: System.out.println("???"); break; }
Refer to page 109 in the text.
© 2007 Lawrenceville Press

7. Part of the java.lang package
5/13/2018 9:32 PM
Chapter 5 The Math Class
Part of the java.lang package
The random() methods generates a double between 0 and 1.0. For example, double rNum; rNum = Math.random();
A random integer in a range is generated by using the expression: (highNum – lowNum + 1) * Math.random() + lowNum
Refer to pages 110 and 111 in the text.
The Random class actually generates pseudorandom (like random) numbers. Java implements the Linear Congruential Method to ensure that generated numbers can be considered random for most applications.
© 2007 Lawrenceville Press

8. Chapter 5 Compound Boolean Expressions
5/13/2018 9:32 PM
Chapter 5 Compound Boolean Expressions
More than one Boolean expression in a single condition.
Formed using the logical And (&&), logical Or (||), or logical Not (!) operators.
Refer to page 112 in the text.
Compound Boolean expressions use more than one Boolean expression to determine if a condition is true or false.
© 2007 Lawrenceville Press

9. Chapter 5 And Truth Table
5/13/2018 9:32 PM
Chapter 5 And Truth Table
And
Exp1
Exp2
Result
True
False
Refer to page 112 in the text.
© 2007 Lawrenceville Press

10. Or Exp1 Exp2 Result True False Chapter 5 Or Truth Table
5/13/2018 9:32 PM
Chapter 5 Or Truth Table Or
Exp1
Exp2
Result
True
False
Refer to page 112 in the text.
© 2007 Lawrenceville Press

11. Chapter 5 Not Truth Table
5/13/2018 9:32 PM
Chapter 5 Not Truth Table
Not
Exp
Result
True
False
Refer to page 112 in the text.
© 2007 Lawrenceville Press

12. Part of the java.lang package Methods include:
5/13/2018 9:32 PM
Chapter 5 The Math Class
Part of the java.lang package
Methods include:
abs(num) returns the absolute value of num
pow(num1, num2) returns num1 raised to the num2 power
sqrt(num) returns the square root of num, where num is a positive number
Refer to page 113 in the text.
© 2007 Lawrenceville Press

13. Chapter 5 Flowchart Symbols
5/13/2018 9:32 PM
Chapter 5 Flowchart Symbols
decision
Refer to page 115 in the text.
The diamond flowchart symbol indicates a decision.
© 2007 Lawrenceville Press

14. Chapter 5 The RPS Flowchart
5/13/2018 9:32 PM
Chapter 5 The RPS Flowchart
Refer to page 115 in the text.
The RPS flowchart illustrates the application solution. Solution steps include:
1. prompting the user for a number between 1 and 3
2. generating a random number between 1 and 3
3. comparing the generated number to the number typed by the user
4. determining a winner and displaying an appropriate message
© 2007 Lawrenceville Press