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Accessing Private Data Members in Classes

This code shows you how to access private data members in classes without using the friend keyword.

Submitted By: born2c0de

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Views: 16,139

Language: C++

Last Modified: March 2, 2005

Snippet

/*
ACCESSING PRIVATE DATA MEMBERS IN C++
-SANCHIT KARVE
born2c0de@hotmail.com
*/
#include <iostream.h>
#include <string.h>
#include <conio.h>
class bestcoder
{
private:
char name[40];
char grade;
int age;
public:
bestcoder(char* nam="Some Dude",char gr='A',int saal=25)
{
strcpy(name,nam);
grade=gr;
age=saal;
}
friend ostream& operator <<(ostream& s,bestcoder b);
};
ostream& operator <<(ostream& s,bestcoder b)
{
s<<"Best Coder :"<<b.name<<endl
<<"His Rating :"<<b.grade<<endl
<<"Current Age :"<<b.age<<"\n\n\n";
return s;
}
struct hackit
{
char name[40];
char grade;
char age;
};
void main()
{
bestcoder bc;
cout<<bc;
void* ptr=&bc;
struct hackit* bettercoder=(hackit*)ptr;
bettercoder->grade='F';
bettercoder->age=56;
cout<<bc;
strcpy(bettercoder->name,"Sanchit Karve");
bettercoder->age=14;
bettercoder->grade='A';
cout<<bc;
getch();
}

Copy & Paste

/*
               ACCESSING PRIVATE DATA MEMBERS IN C++
                                    -SANCHIT KARVE
                                     born2c0de@hotmail.com

#include <iostream.h>
#include <string.h>
#include <conio.h>

class bestcoder
{
  private:

char name[40];
     char grade;
     int age;

public:

bestcoder(char* nam="Some Dude",char gr='A',int saal=25)
      {
         strcpy(name,nam);
         grade=gr;
         age=saal;
      }

friend ostream& operator <<(ostream& s,bestcoder b);
};

ostream& operator <<(ostream& s,bestcoder b)
{
  s<<"Best Coder  :"<<b.name<<endl
       <<"His Rating  :"<<b.grade<<endl
   <<"Current Age :"<<b.age<<"\n\n\n";
   return s;
}

struct hackit
{
  char name[40];
  char grade;
  char age;
};

void main()
{
 bestcoder bc;
 cout<<bc;
 void* ptr=&bc;
 struct hackit* bettercoder=(hackit*)ptr;
 bettercoder->grade='F';
 bettercoder->age=56;
 cout<<bc;
 strcpy(bettercoder->name,"Sanchit Karve");
 bettercoder->age=14;
 bettercoder->grade='A';
 cout<<bc;
 getch();
}

Comments
aquene533 2007-12-07 22:41:12
I made a small error when I defined my friend member function in main... the examples provided me with the insight necessary to track down and correct my silly error! Thank you! This website is a great resource!
Kingsman1 2009-01-04 23:15:37
This is so cool! I cannot find anything like this in any C++ programming books I read. One book did say it is possible, but it did not show me how. Thank you for teaching me this interesting aspect of the C++ language. Just one small typo: I believe line 46 above meant "int age;" instead of "char age;". The surprising thing is with the above typo, the C++ compiler still let me cast the NULL pointer into a hackit pointer. No error. The code still runs without an exact match. Amazing!