AP Computer Science A:: Boolean If

What must a BOOLEAN EXPRESSION evaluate to in Java?

- **A)** Either \(true\) or \(false\) -- no other value is possible
- **B)** Either \(0\) or \(1\), stored as integers
- **C)** A \(String\)
- **D)** Any \(int\) value

What is the general syntax of a basic \(if\) statement in Java?

- **A)** \(if\ \{booleanExpression\}\ statements;\)
- **B)** \(if\ booleanExpression\ then\ statements;\)
- **C)** \(if\ (statements)\ \{\ booleanExpression;\ \}\)
- **D)** \(if\ (booleanExpression)\ \{\ statements;\ \}\), where the statements execute ONLY when the boolean expression evaluates to \(true\)

Given \(int\ x = 5;\), what happens when the following code runs? \(if\ (x > 10)\ \{\ System.out.println("big");\ \}\)

- **A)** The program crashes
- **B)** "big" is printed
- **C)** Nothing is printed, since \(x > 10\) evaluates to \(false\) (5 is not greater than 10), so the block is skipped entirely
- **D)** This causes a compile-time error

What is the purpose of the \(else\) clause paired with an \(if\) statement?

- **A)** It is required after every \(if\) statement in Java
- **B)** It specifies a block of code to execute ONLY when the \(if\)'s boolean condition evaluates to \(false\)
- **C)** It specifies code that always executes, regardless of the condition
- **D)** It repeats the \(if\) block multiple times

Given \(int\ score = 55;\), what is printed by: \(if\ (score\ >=\ 60)\ \{\ System.out.println("Pass");\ \}\ else\ \{\ System.out.println("Fail");\ \}\)?

- **A)** Nothing is printed
- **B)** "Pass"
- **C)** Both "Pass" and "Fail" are printed
- **D)** "Fail", since \(55 \geq 60\) is \(false\), so the \(else\) branch executes instead

What is a CASCADING (chained) \(if\)-\(else\ if\)-\(else\) statement used for?

- **A)** It is functionally identical to a series of independent, separate \(if\) statements with no difference in behavior
- **B)** To repeat a block of code a fixed number of times
- **C)** To test a series of conditions IN ORDER, executing only the block associated with the FIRST condition that evaluates to \(true\), and skipping all remaining conditions once a match is found
- **D)** To execute every single block regardless of which conditions are true

Given \(int\ x = 85;\), what grade is printed by: \(if\ (x\ >=\ 90)\ System.out.println("A");\ else\ if\ (x\ >=\ 80)\ System.out.println("B");\ else\ System.out.println("C");\)?

- **A)** "A"
- **B)** "C"
- **C)** "B", since \(85 \geq 90\) is false, but \(85 \geq 80\) is true, so the second branch executes and the chain stops there
- **D)** Both "A" and "B" are printed

Why does the ORDER of conditions matter in a cascading \(if\)-\(else\ if\) chain that assigns letter grades from highest to lowest threshold (90, 80, 70, ...)?

- **A)** Conditions must always be listed in alphabetical order
- **B)** Because only the FIRST true condition's block runs -- if the conditions were instead ordered from LOWEST to HIGHEST threshold, a high score like 95 would incorrectly match the first (lowest) condition it satisfies rather than the intended highest grade
- **C)** The order of conditions in a cascading if-else-if chain never affects the outcome
- **D)** Reordering the conditions would cause a compile-time error