Thread: memory ?

  1. #1
    Registered User
    Join Date
    Aug 2003

    Question memory ?

    I'm new to C++ so first programs naturally include a calculator.
    My memory question is this:
    I have a function for each math procedure(add, sub, mul, div,etc)
    I have globally declared double a, b, ; for use with all the functions. I have read many places to keep the scope of variables as small as possible...So do the values of a, b, accumulate in memory by declaring them globally? :
    0x00001 = a for first function
    0x00002 = b for first function
    0x00003 = a for second function
    0x00004 = b for second function
    or would they over write each other therefore using the same memory space??
    A little confused by this ........appreciate any thoughts.....:^)

  2. #2
    Senior Member joshdick's Avatar
    Join Date
    Nov 2002
    Phildelphia, PA
    Don't declare variables globally. You should declare your variables a and b in the main() function. At the end of the main function, the memory set aside for a and b will be given back to the computer. Look up the reserved words auto, static, and register.

    "The computer programmer is a creator of universes for which he alone is responsible. Universes of virtually unlimited complexity can be created in the form of computer programs." -- Joseph Weizenbaum.

    "If you cannot grok the overall structure of a program while taking a shower, you are not ready to code it." -- Richard Pattis.

  3. #3
    Registered User
    Join Date
    Jan 2003
    when you assign something to the variable it overwrites the previous value... You might want to try not using globals for example...

    #include <stdio.h>
    double add(double a,  double b)
        return a+b;
    int main()
        double x = 25.367, y = 86.254;
        printf("%.3f + %.3f = %.3f\n", x, y, add(x, y));
        return 0;

  4. #4
    Registered User
    Join Date
    Aug 2003

    Thumbs up Re: mem?

    joshdick & Rog
    Thanks for your replys.........
    I looked up those keywords and the info on static answered my question. Thanks again.....

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