Comments on: 8.4 — Access functions and encapsulation

By: zingmars

zingmars — Sat, 08 Oct 2011 13:05:41 +0000

Declaring class members private ensures that only the class members can edit and change it, making it easier to work with the class.

By: Ramseena M.S

Ramseena M.S — Tue, 20 Sep 2011 09:50:20 +0000

Now too I didn’t understand the real usage of declaring class members private

By: DavidE

DavidE — Wed, 24 Aug 2011 04:06:04 +0000

Hey, I have a tip for those who like to consolidate their code. Instead of having both setValue() and getValue() methods, I do this:

getset.h:
#ifndef GETSET_H #define GETSET_H


enum GetOrSet{

	GET,

	SET

};

#endif

main.cpp
#include #include #include "getset.h"


class Employee{

	public:

		char name[25];

		int ID;

		double wage;

		void setInfo(char *name, int ID, double wage){

			strncpy(Employee::name, name, 25);

			Employee::ID = ID;

			Employee::wage = wage;

		}
		double Wage(GetOrSet option, double value=0){
			if(option == GET)

				return Employee::wage;

			else if (option == SET)

				Employee::wage = value;

		}
		void toString(){

			std::cout << "Name:\t" << name << std::endl << "ID:\t" << ID << std::endl << "Wage:\t$" << wage;

		}

};
inline void pause(){
	std::cout << std::endl;

	system("PAUSE");

}
int main(int argc, char* argv[]){
	Employee Alex;

	Alex.setInfo("Alex", 1, 38.00);

	Employee Jack;

	Jack.setInfo("Jack",2, 22.25);

	Jack.Wage(SET,50.0);

	Alex.toString();

	std::cout << std::endl;

	Jack.toString();

	std::cout << std::endl;

	std::cout << Alex.Wage(GET);

pause(); return 0; }

By: yogendra

yogendra — Sun, 03 Oct 2010 13:12:39 +0000

great tutorial…..
It gave me clear idea of what inheritance is and also
the most basic difference between c and c++ is the
code maintainability achieved through inheritance

By: Bob

Bob — Mon, 06 Sep 2010 13:39:44 +0000

#include

By: Tom

Tom — Fri, 03 Sep 2010 16:29:29 +0000

When I try the “fixed example”

class Change
{
private:
    int m_nValue;

public:
    void SetValue(int nValue) { m_nValue = nValue; }
    int GetValue() { return m_nValue; }
};

int main()
{
    Change cChange;
    cChange.SetValue(5);
    std::cout << cChange.GetValue() << std::endl;
}

I get the errors:

g++ j39.cpp -g -o xxx
j39.cpp: In function ‘int main()’:
j39.cpp:15: error: ‘cout’ is not a member of ‘std’
j39.cpp:15: error: ‘endl’ is not a member of ‘std’

By: AsianBorat

AsianBorat — Mon, 30 Aug 2010 00:50:48 +0000

This tutorial is incredible. This article didn’t just explain encapsulation. It gave me a clear example, which FINALLY made me understand why encapsulation is so necessary.

By: Balu Nair

Balu Nair — Sun, 15 Aug 2010 15:16:53 +0000

Hi Alex,

Your article rocks buddy! This article is such a precious gem.

Thanks!!!

By: Henry

Henry — Sun, 02 May 2010 07:55:10 +0000

Hmm when i ran the last example – i got like -858993460. Any ideas?

By: yogal

yogal — Tue, 23 Feb 2010 13:11:16 +0000

Wow, great explanation of encapsulation, and WHY one would use getters/setters instead of directly accessing members!

One good argument for using encapsulation might be validation. When you have setters set-up you can validate what is passed to members and take appropriate action. Although members have to be of certain type, which provides low-level validation, sometimes you need a more complex requirement!

Take care and thanks for such a wonderful tutorial!