Thread: Static structure

  1. #1
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    Static structure

    Hello everyone,

    I'm trying to accomplish a static structure but fail miserably. If I define them non static everything works as it should, but trying to define it static fails by all google-solutions. Therefore my post here!

    My Code:
    structure in Genre.h
    Code:
    struct genre{
    	int id;
    	string name;
    	int score;
    };
    Code:
    class iDNA {
    	private:
    		static genre _go_genre[1750];
    Code:
    void iDNA::loadDefaults() {
    [...]
    		while (res->next()) {
    			_go_genre[li_count].name = res->getString("name");
    			li_count++;
    		}
    Error:
    iDNA.o: In function `iDNA::loadDefaults()':
    iDNA.cpp: (.text+0x319): undefined reference to `iDNA::_go_genre'
    collect2: ld returned 1 exit status
    make: *** [iDNA] Error 1
    OS: Arch Linux x86
    Compiler: gcc version 4.4.2 (GCC)
    Linker: GNU ld (GNU Binutils) 2.20.0.20091101

    Hopefully I provided enough information. If not just ask for more!


    Thanks in advance,

    Arjan Gelderblom

  2. #2
    C++ Witch laserlight's Avatar
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    You probably forgot to define the array. In a source file, write:
    Code:
    genre iDNA::_go_genre[1750];
    By the way, avoid using names that begin with underscores since they may be reserved to the compiler and standard library implementation. In this case because the underscore is followed by a lowercase letter, and the name is at class scope, it is okay, but still
    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
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    Wow, lightning fast answer! And i

    Quote Originally Posted by laserlight View Post
    You probably forgot to define the array. In a source file, write:
    Code:
    genre iDNA::_go_genre[1750];
    Isn't this done by the first part of the code with:
    Code:
    class iDNA {
    	private:
    		static genre _go_genre[1750];
    Quote Originally Posted by laserlight View Post
    By the way, avoid using names that begin with underscores since they may be reserved to the compiler and standard library implementation. In this case because the underscore is followed by a lowercase letter, and the name is at class scope, it is okay, but still
    Thanks for pointing this out... Will change this right away!

    Thanks, Bloged

  4. #4
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by Bloged
    Isn't this done by the first part of the code with:
    No, that is just a declaration.
    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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