How do I make a class call it's own address

This is a discussion on How do I make a class call it's own address within the C++ Programming forums, part of the General Programming Boards category; I would like to make a class and have it store it's own memory address as a private data member ...

  1. #1
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    How do I make a class call it's own address

    I would like to make a class and have it store it's own memory address as a private data member automatically when it is created. Additionally I would like to make a function within that same class which, when called on, can determine it's memory address and store it in the private date member. Is there a way to do this?

  2. #2
    Just Lurking Dave_Sinkula's Avatar
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    Maybe something like this?
    Code:
    #include <iostream>
    
    class T
    {
       T *address;
       void (T::*mypfoo)();
    public:
       T() : address(this)
       {
          std::cout << "address = " << address << '\n';
       }
       void foo()
       {
          mypfoo = &T::foo;
       }
    };
    
    int main()
    {
       T a, b, c;
       a.foo();
       b.foo();
       c.foo();
       return 0;
    }
    
    /* my input/output
    address = 0012FF88
    address = 0012FF84
    address = 0012FF80
    */
    http://www.parashift.com/c++-faq-lit...o-members.html
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

  3. #3
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    My understanding is that you just want the memory address of the class instance, not of the member functions. In that case it is already stored (no need for a private variable). The keyword 'this' is a pointer to the current object instance, and you can use it as the address of the instance.

  4. #4
    Registered User
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    As I understand, C++ simulates reference passing with pointers. When you call member functions of a class, you are essentially calling a global function with the particular instance of the class passed by reference as an argument.

    There is also a way to get the addresses of member functions, if that's what you want. (Function pointers.) I think you can only do that outside of the member function, though. However, you can try to create a function object with a constructor (to get its address) and oerloaded operator(), and use a static instance for each class. The syntax might be a little convoluted, so you should have a very good reason for wanting to do this.
    Code:
    #include <stdio.h>
    
    void J(char*a){int f,i=0,c='1';for(;a[i]!='0';++i)if(i==81){
    puts(a);return;}for(;c<='9';++c){for(f=0;f<9;++f)if(a[i-i%27+i%9
    /3*3+f/3*9+f%3]==c||a[i%9+f*9]==c||a[i-i%9+f]==c)goto e;a[i]=c;J(a);a[i]
    ='0';e:;}}int main(int c,char**v){int t=0;if(c>1){for(;v[1][
    t];++t);if(t==81){J(v[1]);return 0;}}puts("sudoku [0-9]{81}");return 1;}

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