It is good practice to make clear how we expect variables to be manipulated. In the case of classes and objects, it is good practice to define set and get methods that assign (set) values of our variables and retreive (get) values of variables. In this way we can also define variables to be private: members of our class, which ensures that there is only one mechanism to update variable values are through set and get methods. This coding paradigm helps reminds ourselves and other programmers of the code if the intended approach for accessing variables.

// https://www.w3schools.com/cpp/cpp_encapsulation.asp
#include <iostream>
using namespace std;

class Employee {

  private:
    int salary;

  public:
  
    // setter
    void setSalary(int s){
      salary = s;
    }

    // getter
    int getSalary(){
      return salary;
    }



};

int main(){  

  Employee John;
  John.setSalary(3000);
  cout << John.getSalary() << "\n";

  return 0;
}
// 3000

In the example above, we define a public setter using the set phrase in setSalary() and we define a getter using the get phrase in getMethod(). The setter and getter only have a single operation to perform (assigning, and returning a value). The variable salary never needs to be accessed outside the class and is therefore define as a private: member.

• C++ Encapsulation - w3schools.com