Variable Call via Another Variable's Content

This is a discussion on Variable Call via Another Variable's Content within the C++ Programming forums, part of the General Programming Boards category; Hello! Does anyone know of a way to call (or create) a variable by using the *contents* of another variable, ...

  1. #1
    Registered User
    Join Date
    Jan 2005
    Posts
    2

    Variable Call via Another Variable's Content

    Hello!

    Does anyone know of a way to call (or create) a variable by using the *contents* of another variable, presumably a concatenated string?
    An attempt I didn't expect to work is below to clarify...if it clarifies.

    Code:
    #include <cstdlib>
    #include <iostream>
    
    using namespace std;
    
    int main(int argc, char *argv[])
    {
        const char a='B';
        const int B=99;
        const char* A=a;
        int ending;
        cout << a << ": Should read 'B'" << endl;
        cout << B << ": Should read '99'" << endl;
        cout << A << ": Should read 'B'" << endl;
        cout << *A << ": Should read 'B'" << endl;
        cout << &A << ": Should read some memory address crap" << endl;
        //cout << *a << endl;
        cout << "Press enter to end program" endl;
        cin >> ending
        system("PAUSE");
        return EXIT_SUCCESS;
    }
    Does what I'm asking make sense? Is there a way to do it?
    Thanks muchly!

  2. #2
    Registered User Kybo_Ren's Avatar
    Join Date
    Sep 2004
    Posts
    136
    Code:
    const char* A=&a;
    Will have A be an unchangeable pointer to the character variable a.

    However, this is just a pointer. I think you want to do something like:
    Code:
    const char a = 'B';
    
    char thestring[50];
    
    thestring[0] = a;
    thestring[1] = '\0';//make sure you add the null
    
    strcat(thestring, "ecause I said so.");//this will concatenate to the string.
    
    //now thestring is an array that contains "Because I said so."
    However, that's the C-style way. The standard C++ approach is something like:
    Code:
    std::string thestring(1u, a);//create a string with 1 of the variable a's in it
    
    thestring += "ecause I said so.";//add this to thestring
    
    //now thestring has a value of "Because I said so."
    //be careful, though.  If you want to access a std::string like a C-style string, you should use
    //the member function c_str().
    //an example:
    char string2[50];
    
    strcpy(string2, thestring.c_str());
    Note that the above code isn't the best -- it can definitely be made better by using dynamic allocation, but I decided to stick with simplicity here.
    Last edited by Kybo_Ren; 01-12-2005 at 10:12 PM. Reason: fixed table breaks

  3. #3
    Registered User
    Join Date
    Jan 2005
    Posts
    2

    Alright; what about creating dynamic or variable-variables?

    Thanks Kybo_Ren,

    That will definitely help me in getting the strings right, but I'm still in the dark about creating a variable using the contents of one variable as the name of the new one.

    Code:
    char x[50];
    x[0]='F';
    x[1]='/0'; //could I just do x[0]='F/0'?
    strcat(x, 'rank');
    //good to here. I have x=Frank thus far
    Now, conceptually, I want to declare a variable named "Frank". But I don't just want:

    Code:
    int Frank=2;
    I want something more like:

    Code:
    int somesupermagictricktousethecontentsof(x)=2;
    cout<<Frank; //displaying the value 2
    This way I can do fancier things. Does C++ have a way to accomplish this? Or perhaps..perhaps I need to write a function that returns the content of x and use it like I did just above....

    Any further advice?

    ~E-Rac

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Call a funvtion from a variable
    By Phoenix_Rebirth in forum C Programming
    Replies: 4
    Last Post: 01-18-2009, 06:22 AM
  2. Variable Properties vs Public Variables
    By Rainbowinblack in forum C# Programming
    Replies: 2
    Last Post: 02-19-2008, 12:48 PM
  3. Working with variable variables
    By Differentialpi in forum C Programming
    Replies: 1
    Last Post: 01-06-2008, 09:35 PM
  4. accessing the variables in variable length parameters
    By Dave Jay in forum C Programming
    Replies: 4
    Last Post: 03-13-2005, 12:36 AM
  5. Pls help me to do this project in C I need source code
    By sureshmenon74 in forum C Programming
    Replies: 4
    Last Post: 10-04-2001, 06:57 AM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21