CS203 – Lab Code Output Analysis Practice Test

Section 1: Basic Java Programs Lab 1

FirstJavaProgram.java, Numbers.java, Fibonacci.java — println, for loops, variables

Question 1 FirstJavaProgram.java

What is the output of this program?

public class FirstJavaProgram {
    public static void main(String[] args) {
        System.out.println("CS 203 First JAVA program !!! ");
    }
}

CS 203 First JAVA program !!!
CS 203 First JAVA program !!! (with trailing space)
Nothing — it doesn't compile
CS203FirstJAVAprogram!!!

Question 2 Numbers.java

What value is printed by this program?

public class Numbers {
    public static void main(String[] args) {
        int x = 100;
        int sum = 0;
        for (int i = 0; i <= x; i++) {
            sum = sum + i;
        }
        System.out.println(sum);
    }
}

4950
5050
100
5000

Question 3 Numbers.java

In Numbers.java, if we changed the loop condition to i < x (strictly less than), what would be printed?

for (int i = 0; i < x; i++) {  // changed from i <= x
    sum = sum + i;
}

5050
4950
100
5000

Question 4 Fibonacci.java

If the user enters 5 for n, what is printed?

int first = 0;
int second = 1;
for (int i = 1; i <= n; i++) {
    System.out.print(first + " ");
    int next = first + second;
    first = second;
    second = next;
}

0 1 1 2 3
1 1 2 3 5
0 1 1 2 3 5
0 1 2 3 5

Question 5 Fibonacci.java

In Fibonacci.java, what is the difference between System.out.print() and System.out.println()?

print() does not move to the next line; println() moves to the next line after printing
They are identical
print() only prints integers; println() prints any type
println() does not move to the next line; print() does

Question 6 Fibonacci.java

In Fibonacci.java, what is the purpose of Scanner scanner = new Scanner(System.in)?

It prints output to the console
It reads input from the user via the keyboard
It creates a random number
It opens a file for reading

Section 2: Classes, Constructors & Getters/Setters Lab 3

Book.java, BookTester.java — Object creation, accessors/mutators, state changes

Question 7 Book.java

In the Book class, all member variables are declared as private. Why?

public class Book {
    private String name;
    private int page;
    private boolean stock;
    // ...
}

So no code at all can access the data
To enforce encapsulation — only the Book class can directly access these variables; external code must use getters/setters
It's required syntax — Java won't compile without it
To make them shared across all Book objects

Question 8 BookTester.java

What does the following line output?

Book myBook = new Book("The Great Gatsby", 180, true);
System.out.println("Book Name: " + myBook.getName());

Book Name: null
Book Name: The Great Gatsby
The Great Gatsby
A compilation error

Question 9 BookTester.java

After running these lines, what does myBook.getPage() return?

Book myBook = new Book("The Great Gatsby", 180, true);
myBook.setPage(200);

180
200
0
null

Question 10 BookTester.java

What is the full console output of BookTester's "Updated Values" section?

myBook.setPage(200);
myBook.setStock(false);

System.out.println("--- Updated Values ---");
System.out.println("Book Name: " + myBook.getName());
System.out.println("Page Count: " + myBook.getPage());
System.out.println("In Stock: " + myBook.getStock());

Book Name: The Great Gatsby, Page Count: 180, In Stock: true
Book Name: The Great Gatsby, Page Count: 200, In Stock: false
Book Name: null, Page Count: 200, In Stock: false
Book Name: The Great Gatsby, Page Count: 200, In Stock: true

Question 11 Book.java

In Book.java, is setPage(int p) an accessor or a mutator method?

public void setPage(int p) {
    page = p;
}

Accessor — it returns data without changing state
Mutator — it changes the internal data (page) and returns void
Neither — it is a constructor
Both accessor and mutator

Section 3: Inheritance & Overriding Lab 4

GameCharacter.java, BossCharacter.java, GameTester.java — extends, super(), @Override, method overloading

Question 12 GameCharacter.java

What does attack() return in the GameCharacter class?

public int attack() {
    return 10;
}

0
10
20
30

Question 13 BossCharacter.java

BossCharacter overrides attack(). What does boss.attack() return?

@Override
public int attack() {
    return super.attack() + 20;
}

10
20
30
40

Question 14 GameTester.java

What is the output of this line?

BossCharacter boss = new BossCharacter("Dragon Lord", 500);
System.out.println("Attack Damage: " + boss.attack());

Attack Damage: 10
Attack Damage: 20
Attack Damage: 30
Attack Damage: 500

Question 15 GameTester.java

BossCharacter has getType() (inherited, no args) and getType(boolean detailed) (its own). What does boss.getType() output?

// Inherited from GameCharacter:
public String getType() { return "Game Character"; }

// Defined in BossCharacter (different signature — has a parameter):
public String getType(boolean detailed) { ... }

Boss Character
Game Character
Boss Character with High Damage
Compilation error

Question 16 GameTester.java

What does boss.getType(true) return?

public String getType(boolean detailed) {
    if (detailed == true) {
        return "Boss Character with High Damage";
    } return "Boss Character";
}

Game Character
Boss Character
Boss Character with High Damage
null

Question 17 GameTester.java

What does boss.getType(false) return?

Game Character
Boss Character
Boss Character with High Damage
null

Question 18 BossCharacter.java

The BossCharacter has getType() (no args, inherited) and getType(boolean) (its own). This is an example of:

Method overriding — same name, same parameters, different implementation
Method overloading — same name, different parameters
Encapsulation — hiding data behind methods
Abstraction — reducing complexity

Question 19 BossCharacter.java

Why does BossCharacter's constructor call super(name, health)?

public BossCharacter(String name, int health) {
    super(name, health);
}

Because constructors are not inherited — BossCharacter must explicitly call the parent's constructor to initialize name and health
It's optional and has no effect
It creates a second GameCharacter object
It overrides the parent constructor

Question 20 GameCharacter.java

Can BossCharacter directly access name or health from GameCharacter?

// In GameCharacter:
private String name;
private int health;

Yes — subclasses can access all parent variables
No — they are private; BossCharacter must use getName() and getHealth()
Yes — but only inside the constructor
No — private variables don't exist in subclasses at all

Section 4: Inheritance & Method Calls Lab 6

Calculator.java, ScientificCalculator.java, CalculatorTester.java — super, inherited methods, division

Question 21 Calculator.java

Given Calculator calc = new Calculator(10, 3), what does calc.add() return?

public int add() {
    return this.num1 + this.num2;
}

10
13
3
30

Question 22 Calculator.java

Given Calculator calc = new Calculator(10, 3), what does calc.divide() return?

public double divide() {
    if (this.num2 == 0) {
        return 0.0;
    }
    return (double) this.num1 / this.num2;
}

3 (integer division)
3.3333... (approximately)
0.0
A runtime error

Question 23 Calculator.java

What does calc.divide() return if num2 is 0?

It throws an ArithmeticException
0.0
Infinity
null

Question 24 Calculator.java

Why does the divide() method cast this.num1 to (double)?

return (double) this.num1 / this.num2;

It doesn't matter — integer division would give the same result
To force floating-point division so the result includes the decimal portion (e.g., 3.33 instead of 3)
To convert the result to a String
Because num1 is a double variable

Question 25 ScientificCalculator.java

ScientificCalculator extends Calculator. Can a ScientificCalculator object call add()?

public class ScientificCalculator extends Calculator {
    public ScientificCalculator(int a, int b) {
        super(a, b);
    }
    // only defines square_root() and exponentiation()
}

No — ScientificCalculator doesn't define add()
Yes — it inherits add() from Calculator
Only if you cast it to Calculator first
Yes, but it returns 0

Question 26 ScientificCalculator.java

Given ScientificCalculator sc = new ScientificCalculator(9, 2), what does sc.square_root() return?

public double square_root() {
    return Math.sqrt(get_first_number());
}

3.0
4.5
81.0
1.414...

Question 27 ScientificCalculator.java

Given ScientificCalculator sc = new ScientificCalculator(9, 2), what does sc.exponentiation() return?

public double exponentiation() {
    return Math.pow(get_first_number(), get_second_number());
}

18.0 (9 * 2)
81.0 (9²)
11.0 (9 + 2)
512.0 (2⁹)

Question 28 ScientificCalculator.java

In square_root(), why does ScientificCalculator call get_first_number() instead of directly accessing num1?

num1 is private in Calculator — the subclass cannot access it directly and must use the public getter
It's just a style choice — accessing num1 directly would also work
get_first_number() returns a different value than num1
It would cause a runtime error to access num1

Question 29 Calculator.java

After running this code, what does calc.get_first_number() return?

Calculator calc = new Calculator(10, 5);
calc.set_first_number(25);

10
25
5
0

Section 5: Loop & Logic Tracing Homework 1

hw1_strachan.java — trace for loops, while loops, conditionals, and string processing

Question 30 hw1_strachan.java — numSteps

Trace through numSteps(14). What is returned?

public static int numSteps(int n) {
    int steps = 0;
    while (n > 0) {
        if (n % 2 == 0) {
            n = n / 2;
        } else {
            n = n - 1;
        }
        steps++;
    }
    return steps;
}
// n: 14→7→6→3→2→1→0  steps: 6

4
6
7
14

Question 31 hw1_strachan.java — countVowelsConsonants

What does countVowelsConsonants("hello") print?

public static void countVowelsConsonants(String s) {
    int v = 0; int c = 0;
    s = s.toLowerCase();
    for (int i = 0; i < s.length(); i++) {
        char letter = s.charAt(i);
        if (letter == 'a' || letter == 'e' || letter == 'i'
            || letter == 'o' || letter == 'u') {
            v++;
        } else if (letter >= 'a' && letter <= 'z') {
            c++;
        }
    }
    System.out.println(v + "," + c);
}
// "hello" → h(c), e(v), l(c), l(c), o(v)

2,3
3,2
1,4
5,0

Question 32 hw1_strachan.java — countVowelsConsonants

What does countVowelsConsonants("java") print?

2,2
3,1
1,3
4,0

Question 33 hw1_strachan.java — blazerNumber

The blazerNumber method sums divisors of n (less than n). It returns true if the sum does NOT equal n, false if it does. What does blazerNumber(6) return?

// Divisors of 6 less than 6: 1, 2, 3
// Sum = 1 + 2 + 3 = 6
// sum == n → return false (it IS a "perfect number")

true
false
6
0

Question 34 hw1_strachan.java — findLargestPrime

What does findLargestPrime(20) return?

public static int findLargestPrime(int maxNum) {
    for (int i = maxNum; i > 1; i--) {
        boolean isPrime = true;
        for (int j = 2; j < i; j++) {
            if (i % j == 0) { isPrime = false; break; }
        }
        if (isPrime) { return i; }
    }
    return 0;
}
// Checks 20(no), 19(yes!) → returns 19

17
19
20
23

Question 35 hw1_strachan.java — countVowelsConsonants

The countVowelsConsonants method calls s.toLowerCase() before processing. Why?

To convert numbers to letters
So the vowel/consonant checks only need to compare against lowercase letters — works regardless of the original case of the input
It removes whitespace from the string
It reverses the string

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