Primitive data types in Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of integer division and casting

What is the output of this Java code snippet?

Java

public class Main {
    public static void main(String[] args) {
        int a = 7;
        int b = 2;
        double c = a / b;
        System.out.println(c);
    }
}

A 3.5

B 3.6

C 3

D 3.0

💡 Hint

Remember that dividing two integers results in an integer before assignment.

In Java, dividing two integers performs integer division, so 7 / 2 equals 3. Assigning this to a double variable converts 3 to 3.0.

❓ Predict Output

intermediate

Output of char arithmetic

What is the output of this Java code?

Java

public class Main {
    public static void main(String[] args) {
        char ch = 'A';
        int result = ch + 2;
        System.out.println(result);
    }
}

A 65

B C

C 67

D 2

💡 Hint

Remember that char is treated as a number in arithmetic.

The char 'A' has ASCII value 65. Adding 2 results in 67, which is printed as an int.

❓ Predict Output

advanced

Output of boolean logic with primitives

What is the output of this Java program?

Java

public class Main {
    public static void main(String[] args) {
        boolean a = true;
        boolean b = false;
        boolean c = a && !b || b;
        System.out.println(c);
    }
}

A true

B false

C null

D Compilation error

💡 Hint

Evaluate the boolean expression step by step.

a is true, b is false, so !b is true. Then a && !b is true && true = true. true || false is true.

❓ Predict Output

advanced

Output of float precision and casting

What is the output of this Java code?

Java

public class Main {
    public static void main(String[] args) {
        float f = 1.23456789f;
        double d = f;
        System.out.println(d);
    }
}

A 1.234567

B 1.2345679

C 1.23456789

D 1.234568

💡 Hint

Float has less precision than double.

The float value loses precision beyond 7 digits. When assigned to double, it keeps the float precision, printing approximately 1.2345679.

🧠 Conceptual

expert

Memory size of primitive types

Which primitive data type in Java uses the most memory?

A double

B int

C long

D float

💡 Hint

Think about the number of bytes each type uses.

double uses 8 bytes (64 bits), which is more than int (4 bytes) and float (4 bytes). Although long and double both use 8 bytes, double stores floating-point numbers, so it is considered the largest in terms of precision.