int a = 7;
int b = 2;
double avg = a / b;
System.out.println(avg);

String word = "Computer";
System.out.println(word.substring(0, 4).toUpperCase());

int x = 17;
int result = (x / 5) * 5 + (x % 5);

1. Math.abs(p)
2. Math.pow(q, 3)
3. Math.sqrt(25.0)

String name = null;
int len = name.length();
System.out.println(len);

int m = 3;
int n = 4;
System.out.println("Sum: " + m + n);
System.out.println("Sum: " + (m + n));

double d = 9.99;
int z = (int)(d * 10) % 7;

int alpha = 10;
int beta = 3;
alpha -= beta;
beta *= alpha;
alpha += beta;

1. alpha equals 28
2. beta equals 21
3. alpha + beta equals 49

public static int doubleAbs(int val) {
    if (val < 0) {
        val = -val;
    }
    val = val * 2;
}

int score = 85;
String grade;
if (score >= 90) {
    grade = "A";
}
if (score >= 80) {
    grade = "B";
}
if (score >= 70) {
    grade = "C";
}
else              { grade = "F"; }
System.out.println(grade);

1. x <= 5 || y > 10
2. !(x > 5) || !(y <= 10)
3. x <= 5 && y > 10

int ctr = 1, total = 0;
while (ctr <= 5) {
    if (ctr % 2 != 0) {
        total += ctr;
    }
    ctr++;
}
System.out.println(total);

int count = 0;
for (int r = 0; r < 4; r++) {
    for (int c = r; c < 4; c++) {
        count++;
    }
}
System.out.println(count);

int product = 1;
for (int k = 1; k <= 6; k++) { product *= k; }

1. int k = 1, product = 1;
   while (k <= 6) { product *= k; k++; }

2. int k = 1, product = 1;
   while (k < 7) { k++; product *= k; }

3. int k = 0, product = 1;
   while (k < 6) { k++; product *= k; }

public static String mystery(String s) {
    String result = "";
    for (int i = s.length() - 1; i >= 0; i -= 2) {
        result += s.charAt(i);
    }
    return result;
}

boolean r = (x != 0) && (getValue() > 0);

1. r is false
2. getValue() is NOT called due to short-circuit evaluation
3. "called" is printed to the console

int p = 6, q = 4;
if (p > 5) {
    if (q > 5) {
        System.out.println("A");
    }
    else        { System.out.println("B"); }
} else if (p > 3) {
    System.out.println("C");
} else {
    System.out.println("D");
}

int n = 16;
int count = 0;
while (n > 1) {
    n = n / 2;
    count++;
}
System.out.println(count);

public class Thermometer {
    private double temperature;

    public Thermometer(double temperature) {
        temperature = temperature;
    }
}

1. c1.getCount() returns 2
2. c2.getCount() returns 0
3. c1 and c2 refer to the same object in memory

public class BankAccount {
    private double balance;

    public boolean isRich(double threshold) {
        if (balance > threshold) {
            return true;
        } else if (balance < threshold) {
            return false;
        }
    }
}

Dog d = new Dog("Rex", 3);
System.out.println(d);

1. r.area() returns 24
2. r.perimeter() returns 20
3. r.width can be accessed directly from client code

public class Coin {
    private String side = "heads";

    public void flip() {
        side = (Math.random() < 0.5) ? "tails" : "heads";
    }

    public static String getSide() {
        return side;
    }
}

public class Multiplier {
    private int factor;
        public Multiplier(int f) {
        factor = f;
    }
        public int apply(int n) {
        return n * factor;
    }
    public Multiplier combine(Multiplier other) {
        return new Multiplier(factor * other.factor);
    }
}
// Client:
Multiplier triple = new Multiplier(3);
Multiplier dbl    = new Multiplier(2);
Multiplier six    = triple.combine(dbl);
System.out.println(six.apply(5));

1. Car c = new Car("Toyota", 2024);
2. Car c = new Car(2024, "Toyota");
3. Car c = new Car("Honda", 1999);

String s1 = new String("hello");
String s2 = new String("hello");
if (s1 == s2) {
    System.out.println("equal");
} else {
    System.out.println("not equal");
}

int[] nums = {10, 20, 30, 40, 50};
for (int i = 0; i <= nums.length; i++) {
    System.out.println(nums[i]);
}

int[] data = {3, 1, 4, 1, 5, 9, 2, 6};
int maxVal = data[0];
for (int val : data) {
    if (val > maxVal) {
        maxVal = val;
    }
}
System.out.println(maxVal);

int[] scores = {70, 80, 90};
for (int s : scores) {
    s = s * 2;
}
System.out.println(scores[0]);

1. words.size() returns 3
2. words.get(0) returns "cat"
3. words.get(1) returns "dog"

ArrayList nums = new ArrayList<>(Arrays.asList(1,2,3,4,5,6));
for (int i = 0; i < nums.size(); i++) {
    if (nums.get(i) % 2 == 0) {
        nums.remove(i);
    }
}

int[][] grid = {{1,2,3},{4,5,6},{7,8,9}};
int total = 0;
for (int r = 0; r < grid.length; r++) {
    total += grid[r][r];
}
System.out.println(total);

1. Arrays have a fixed size; ArrayLists can grow and shrink dynamically.
2. Arrays can hold primitive types; ArrayLists require wrapper classes such as Integer.
3. ArrayLists are faster than arrays when accessing elements by index.

ArrayList list = new ArrayList<>();
list.add(10);
list.add(20);
list.add(30);
list.add(0, 5);
list.set(2, 25);
list.remove(3);

public static int countTarget(int[][] matrix, int target) {
    int count = 0;
    for (int r = 0; r < matrix.length; r++) {
        for (int c = 0; c < matrix.length; c++) {
            if (matrix[r][c] == target) {
                count++;
            }
        }
    }
    return count;
}

1. arr.length returns 5
2. arr[arr.length - 1] returns 8
3. arr[5] returns 0 because it is beyond the last initialized element