Java Basics Practice

Practise Java variables, data types, arithmetic, integer division, casting, string conversion and formatted output.

Beginner7 problemsUpdated October 23, 2026

Review first: Variables, Data Types, Operators, Type Casting, Constants and final

1.Split the bill

Beginner

A dinner costs 1850 rupees and 4 friends split it equally. Print each share with exactly two decimal places, like Each person pays 462.50.

Show hint

Divide as a double, and format with System.out.printf("%.2f%n", value).

Show solution

Java

public class Main {
    public static void main(String[] args) {
        double total = 1850;
        int people = 4;
        System.out.printf("Each person pays %.2f%n", total / people);
    }
}

Output

Each person pays 462.50

2.Minutes to hours and minutes

Beginner

A film lasts 135 minutes. Print it as 2 h 15 min.

Show hint

Integer / gives whole hours; % gives the remaining minutes.

Show solution

Java

public class Main {
    public static void main(String[] args) {
        int minutes = 135;
        System.out.println(minutes / 60 + " h " + minutes % 60 + " min");
    }
}

Output

2 h 15 min

3.Fix the average
Beginner
The average of the marks 7, 8 and 10 should be about 8.33, but int sum = 25; double avg = sum / 3; gives 8.0. Print the wrong result and the correct one.
Show hint
Cast one operand to double before dividing.
Show solution
Java
public class Main { public static void main(String[] args) { int sum = 7 + 8 + 10; double wrong = sum / 3; double right = (double) sum / 3; System.out.println(wrong); System.out.println(right); } }
Output
8.0 8.333333333333334
Java prints a double with as many digits as needed to identify it exactly, which is why the correct average shows many 3s. Use printf("%.2f", ...) to round the display.

4.Text to numbers

Beginner

Given String a = "42"; and String b = "8";, print what a + b gives, then convert both with Integer.parseInt and print their real sum.

Show hint

+ joins strings. Convert first, then add.

Show solution

Java

public class Main {
    public static void main(String[] args) {
        String a = "42";
        String b = "8";
        System.out.println(a + b);
        System.out.println(Integer.parseInt(a) + Integer.parseInt(b));
    }
}

Output

428
50

5.Avoid integer overflow
Beginner
A platform has 2_500_000 users who each watch 1_200 seconds a day. Print the total seconds per day correctly, and also print what happens if you multiply two ints.
Show hint
Cast to long before multiplying: (long) users * seconds.
Show solution
Java
public class Main { public static void main(String[] args) { int users = 2_500_000; int seconds = 1_200; long correct = (long) users * seconds; int overflowed = users * seconds; System.out.println(correct); System.out.println(overflowed); } }
Output
3000000000 -1294967296
3,000,000,000 is larger than Integer.MAX_VALUE (2,147,483,647), so the int multiplication wraps around to a negative number. Java does not report this error unless you use Math.multiplyExact.

6.Characters are numbers

Beginner

Given char letter = 'C';, print the next letter and the numeric code of letter.

Show hint

letter + 1 is an int; cast it back with (char).

Show solution

Java

public class Main {
    public static void main(String[] args) {
        char letter = 'C';
        char next = (char) (letter + 1);
        int code = letter;
        System.out.println(next + " " + code);
    }
}

Output

D 67

7.Round, floor and ceil

Beginner

For the price 249.75, print Math.round, Math.floor, Math.ceil and the value cast to int.

Show hint

Math.round returns a long; floor and ceil return doubles; a cast truncates.

Show solution

Java

public class Main {
    public static void main(String[] args) {
        double price = 249.75;
        System.out.println(Math.round(price));
        System.out.println(Math.floor(price));
        System.out.println(Math.ceil(price));
        System.out.println((int) price);
    }
}

Output

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