(C++)++ Course

What is an Object

1/8

Yes, objects are like real-world items, which is a great way to think of them, but SoloLearn only mentions in one or two sentences in this module that objects can also represent non-physical items as well. This is important to understand because most object-oriented programming is built for non-physical items. It would be better to think of processes or systems that have their own self-contained identities, properties, and behaviors, because that's what happens in the real world of programming. Games will probably use a lot of physical item representations, but they also use OOP for system representation too. For example, saving a game would benefit from what's called serialization, and this is often represented by classes and objects to manage that. It's okay to think about physical items, but it's just as important to think of systems and program management "items" too.

Example of a Class

3/8

I am just going to rewrite SoloLearn's program in ONE code example, instead of split up, because sometimes having it split can be confusing for some:

#include <iostream>
using namespace std;

class BankAccount {
public:
    void sayHi() {
        cout << "Hi" << endl;
    }
};// DON'T FORGET THE SEMICOLON HERE

int main() {
    BankAccount test;
    test.sayHi();
    
    return 0;
}

Abstraction

4/8

I wanted to note that yes, it is good practice to "hide" as much as possible in your classes, but for your own classes it isn't exactly necessary, so if you find it difficult to implement abstraction in your own classes, you don't have to! Just practice some more until you get it. If you know abstraction, it will be a good interviewing concept to have.

Example of Encapsulation

6/8

It's not really encapsulation if you use getters and setters to modify and return class attributes. You might as well make the attribute public and set it that way; setters are just an annoying extra layer. What you want to do is define HOW to modify private attributes.

#include <iostream>
using namespace std;

class BankAccount {
private:
    int balance;
public:
    void startingBal() {
        balance = 200;
    }
    void withdrawal(int x) {
        cout << "Balance before: " << balance << endl;
        if (x < 101) {//controlling how balance is changed
            balance -= x;
        }
        cout << "Balance after: " << balance << endl;
        }
    };

int main() {
    BankAccount test;
    test.startingBal();
    test.withdrawal(50);
    
    return 0;
}

Balance before: 200
Balance after: 150

Classes and Objects

C++ Course, Classes and Objects