Programming IV Chapter 3 Review

If Statements

100

What is the correct syntax of an if statement in Java?

if (BooleanExpression) {
    // statement(s)
}

200

Rewrite this as an if-else statement: If temperature is above 100, print “Hot”; otherwise, print “Cool.”

if (temperature > 100) {
    System.out.println("Hot");
} else {
    System.out.println("Cool");
}

300

Explain what a nested if statement is and give a real-world example.

A nested if statement is an if statement inside another if statement.

400

What is a decision structure?

A type of structure allows a program to choose between multiple paths based on a condition.

500

Write a nested if statement that prints:

• "Eligible for discount" if age is 65 or older

• But only if isMember is true

• Otherwise, print the appropriate message explaining why they are not eligible

if (age >= 65) {

    if (isMember) {

        System.out.println("Eligible for discount");

    } else {

        System.out.println("Must be a member to receive discount");

    }

} else {

    System.out.println("Must be 65 or older for discount");

}

Logical & Relational Operators

100

Which operator checks if two values are equal in Java?

==

200

What are 3 values of num that make this true:
num <=2 && num >=1

1, 1.5, 2, ...

300

Write a condition that is true if x is a number outside of 1-16.

if (x < 1 || x > 16)

400

Write a condition that is true only if age is at least 18 and hasID is true.

if (age >= 18 && hasID)

500

Explain the difference between relational operators and logical operators.

Relational operators compare two values and return true or false.
Examples: >, <, ==, !=

Logical operators combine or modify Boolean expressions.
Examples: &&, ||, !

Strings & Comparisons

100

Write an if statement that prints “Hello!” only if userInput equals "Yes" (case-sensitive).

if (userInput.equals("Yes")) {
    System.out.println("Hello!");
}

200

Why can’t you use == to compare Strings in Java?

== compares memory addresses, not content

300

Given "Apple".compareTo("Apricot"), what would the result be (positive, negative, or zero). Explain why.

Negative because 'l' < 'r'

400

Given "apple".compareTo("Apple"), what would the result be (positive, negative, or zero). Explain why.

Because lowercase 'a' > uppercase 'A'

500

Given "caterpillar".compareToIgnoreCase("Cat"), what would the result be (positive, negative, or zero). Explain why.

Positive.  The first three letters match, but "caterpillar" is longer, and longer strings are considered greater.

Switch Statements

100

What is the purpose of the default case in a switch statement?

Executes if no other case matches.

200

What happens if you forget break; after a case?

Execution falls through to the next case(s).

300

Identify the problem in this switch code.

switch (score) {

    case (score > 90):

        grade = 'A';

        break;

    default:

        grade = 'F';

}

case must be a constant value, not an expression. Use if-else instead.

400

What would be printed:

int score = 85;
switch (score / 10) {
    case 10: System.out.println("A+"); break;
    case 9: System.out.println("A"); break;
    case 8: System.out.println("B"); break;
    case 7: System.out.println("C"); break;
    default: System.out.println("F"); break;
}

B

500

What would be printed:

char letter = 'C';
switch (letter) {
    case 'A':
    case 'B':
        System.out.println("Hey");
        break;
    case 'C':
        System.out.println("Here");
    case 'D':
        System.out.println("There");
        break;
    default:
        System.out.println("Hi");
}

Here
There

Debugging & Scope

100

What symbols do you use for a block of code in an if statement?

{}

200

What is wrong with this condition?

if (count < 0 && count > 100)

Cannot be <0 and >100 at the same time. Use || instead.

300

What is my daughter's name?

Bonus for her middle name.

Bonus bonus for her last name.

Hayden Jo Curtis

400

Find the error in this code and explain how to fix it:

int x = 10;
if (x > 5)
    int y = x + 2;
System.out.println(y);

y is declared inside the if without a block, so it is out of scope outside.

500

Explain the difference between a sequence structure and a decision structure.

Sequence structure: statements execute in order.

Decision structure: program chooses a path based on a condition.