Object interaction in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an object of class Car named myCar.

C++

class Car {};

int main() {
    Car [1];
    return 0;
}

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

AmyCar

Bcar1

CCar

Dobject

Attempts:

3 left

💡 Hint

Common Mistakes

Using the class name as the object name.

Forgetting to name the object.

The correct way to create an object named myCar of class Car is Car myCar;.

2fill in blank

medium

Complete the code to call the startEngine method on the object myCar.

C++

class Car {
public:
    void startEngine() {}
};

int main() {
    Car myCar;
    myCar.[1]();
    return 0;
}

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

ArunEngine

BstopEngine

CengineStart

DstartEngine

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong method name.

Forgetting the parentheses after the method name.

To call the method startEngine on the object myCar, use myCar.startEngine();.

3fill in blank

hard

Fix the error in the code to access the speed attribute of the object car1.

C++

class Car {
public:
    int speed;
};

int main() {
    Car car1;
    car1.[1] = 100;
    return 0;
}

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

Acar1.speed

BSpeed

Cspeed

Dthis.speed

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase 'Speed' instead of 'speed'.

Trying to use 'this' pointer outside class methods.

The attribute speed is accessed directly by car1.speed. Inside main, to assign a value, use car1.speed = 100;. The blank is for the attribute name after the dot.

4fill in blank

hard

Fill both blanks to create a method setSpeed that sets the speed attribute.

C++

class Car {
public:
    int speed;
    void [1](int [2]) {
        speed = [2];
    }
};

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

AsetSpeed

Bspeed

CnewSpeed

DupdateSpeed

Attempts:

3 left

💡 Hint

Common Mistakes

Using the attribute name as parameter name without distinction.

Using wrong method names.

The method name is setSpeed and the parameter name is newSpeed. Inside the method, speed = newSpeed; sets the attribute.

5fill in blank

hard

Fill all three blanks to create an object car2, set its speed to 80, and print it.

C++

#include <iostream>

class Car {
public:
    int speed;
    void setSpeed(int s) { speed = s; }
    int getSpeed() { return speed; }
};

int main() {
    Car [1];
    [1].[2](80);
    std::cout << [1].[3]() << std::endl;
    return 0;
}

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

Acar2

BsetSpeed

CgetSpeed

Dspeed

Attempts:

3 left

💡 Hint

Common Mistakes

Using different object names in different places.

Calling methods with wrong names.

Create the object named car2. Call setSpeed(80) on it to set speed. Then call getSpeed() to get the speed and print it.