global variable and prototype

This is a discussion on global variable and prototype within the C++ Programming forums, part of the General Programming Boards category; I have two different codes here: 1) Code: #include <iostream> using namespace std; short Test; //This is the global variable ...

  1. #1
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    global variable and prototype

    I have two different codes here:

    1)
    Code:
    #include <iostream>
    
                      using namespace std;
    
                      short Test; //This is the global variable
    
                      void Testing(); //This is the function
    
                      int main()
                      {
                       blahblahblah
                       }

    2)
    Code:
    #include <iostream>
    
                      using namespace std;
    
                      void Testing(); //This is the function
    
                      short Test; //This is the global variable
                   
                      int main()
                      {
                       blahblahblah
                       }
    Which of the 2 is better? Should the global variable be placed at on top of void Testing or placed below of Testing. I tried it out and both is the same. Is there something which I don't know of? Thanks in advance!

  2. #2
    C++ Witch laserlight's Avatar
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    Neither, if you can reasonably avoid the global variable. Other than that, the placement of the definition of a global variable with respect to the placement of a function declaration (prototype) does not matter.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
    Registered User C_ntua's Avatar
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    I assume you are asking taking into account what looks better?
    I would then say that if you have a big program with a lot of global variables and lost of function declarations, I would personally (others might like sth else) do this:
    1) Put first the function declaration. Most likely when viewing a code you will want to check the global variables more often, so it is a good idea to be nearer main(). And it just seems more right
    2) It is a good idea, in any case, to put labels. Like:
    /********************
    *** functions *******
    *******************/
    void Test();


    /********************
    *** global variables **
    *******************/
    int gb_a, gb_b;

  4. #4
    C++ Witch laserlight's Avatar
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    In a "big" program, the function declarations would be in header files (perhaps within class definitions), with global variables (if any) declared extern and only defined in one source file.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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