Program to interface not implementation in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an interface for payment processing.

LLD

interface PaymentProcessor {
    void [1](double amount);
}

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ApayAmount

BprocessPayment

CmakePayment

DexecutePayment

Attempts:

3 left

💡 Hint

Common Mistakes

Using method names that are too vague or unclear.

Using implementation details in the interface method name.

The method name processPayment clearly describes the action in the interface.

2fill in blank

medium

Complete the code to declare a class that implements the PaymentProcessor interface.

LLD

class CreditCardProcessor implements PaymentProcessor {
    public void [1](double amount) {
        // Implementation details
    }
}

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

ApayAmount

BexecutePayment

CprocessPayment

DmakePayment

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different method name than the interface.

Changing method parameters.

The class must implement the method declared in the interface exactly as named: processPayment.

3fill in blank

hard

Fix the error in the code where the client uses the interface type to call the method.

LLD

PaymentProcessor processor = new CreditCardProcessor();
processor.[1](100.0);

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AprocessPayment

BpayAmount

CmakePayment

DexecutePayment

Attempts:

3 left

💡 Hint

Common Mistakes

Calling a method name that exists only in the implementation class.

Using a method name not declared in the interface.

The client calls the method defined in the interface, which is processPayment.

4fill in blank

hard

Fill both blanks to declare an interface and a class that implements it.

LLD

interface [1] {
    void processPayment(double amount);
}

class [2] implements [1] {
    public void processPayment(double amount) {
        // Implementation
    }
}

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

APaymentProcessor

BCreditCardProcessor

CDebitCardProcessor

DPaymentInterface

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent names between interface and class.

Using generic names that do not describe roles.

The interface is named PaymentProcessor and the class implementing it is CreditCardProcessor.

5fill in blank

hard

Fill all three blanks to create a client code that uses the interface type to call the method.

LLD

public class PaymentClient {
    public static void main(String[] args) {
        [1] processor = new [2]();
        processor.[3](250.0);
    }
}

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

APaymentProcessor

BCreditCardProcessor

CprocessPayment

DDebitCardProcessor

Attempts:

3 left

💡 Hint

Common Mistakes

Using the implementation class type for the variable instead of the interface.

Calling a method not declared in the interface.

The client declares the variable as the interface PaymentProcessor, instantiates CreditCardProcessor, and calls processPayment.