Procedural vs OOP approach in Java - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a procedural method that prints a greeting.

Java

public class Greeting {
    public static void [1]() {
        System.out.println("Hello, world!");
    }
}

Drag options to blanks, or click blank then click option'

Amain

Bgreet

Cprint

Dhello

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'main' instead of a custom method name.

Using 'print' which is not defined here.

The method name should be greet to match the call in procedural style.

2fill in blank

medium

Complete the code to create an object of class Person and call its method.

Java

public class Person {
    public void sayHello() {
        System.out.println("Hi!");
    }

    public static void main(String[] args) {
        Person p = new [1]();
        p.sayHello();
    }
}

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APerson

BHuman

CObject

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different class name like 'Human' or 'Object' which is incorrect here.

To create an object of the class Person, you use new Person().

3fill in blank

hard

Fix the error in the procedural code by completing the method call.

Java

public class Calculator {
    public static int add(int a, int b) {
        return a + b;
    }

    public static void main(String[] args) {
        int result = Calculator.[1](5, 3);
        System.out.println(result);
    }
}

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Aplus

Bsum

Cadd

Dcalculate

Attempts:

3 left

💡 Hint

Common Mistakes

Using method names not defined like 'sum' or 'plus'.

The method defined is named add, so the call must use add.

4fill in blank

hard

Fill both blanks to complete the OOP class with a constructor and a method call.

Java

public class Car {
    private String model;

    public [1](String model) {
        this.model = model;
    }

    public void displayModel() {
        System.out.println("Model: " + [2]);
    }
}

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ACar

Bmodel

Cthis.model

DdisplayModel

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different constructor name.

Using just 'model' instead of 'this.model' inside the method.

The constructor name must match the class name Car, and to access the instance variable inside the method, use this.model.

5fill in blank

hard

Fill all three blanks to create an object, call a method, and print the result.

Java

public class Rectangle {
    private int width;
    private int height;

    public Rectangle(int width, int height) {
        this.width = width;
        this.height = height;
    }

    public int area() {
        return width * height;
    }

    public static void main(String[] args) {
        Rectangle [1] = new Rectangle(4, 5);
        int [2] = [1].area();
        System.out.println([2]);
    }
}

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Arect

Bresult

Darea

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable name for object and result.

Not calling the method correctly.

We create an object named rect, store the area in result, and print rect.