Structures and setting variables

This is a discussion on Structures and setting variables within the Windows Programming forums, part of the Platform Specific Boards category; Okay, I'm currently trying to make a program that uses structures. I've used the help document provided by the complier ...

  1. #1
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    Structures and setting variables

    Okay, I'm currently trying to make a program that uses structures. I've used the help document provided by the complier to give it a try and I know that I've done most of it right. The problem though is that it would appear as though I'm not setting a variable right because it gives the complier error: "expected constructor, destructor, or type conversion before '.' token " ... this is the line of code where the problem is occuring

    Code:
    standard.name = "Standard";
    It also give the error: "expected `,' or `;' before '.' token". I'm assuming that it's something that I'm doing wrong with this line because the lines before it defining the variables inside the structure don't cause any errors.

    Any suggestions?


    And by the way, anyone know how to link a library to a program without creating a project? (For Dev-C++)

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    Can you post the code of your structure declaration and definition.

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    Frequently Quite Prolix dwks's Avatar
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    How is standard.name defined? If it's a char[] array, you likely want to use strcpy() instead of ordinary assignment.

    How is standard defined? It should be an instance of a structure, but your compiler seems to think otherwise.

    And by the way, anyone know how to link a library to a program without creating a project? (For Dev-C++)
    No, not really. I mean you might be able to use a non-standard #pragma directive of some sort, but it would be a hassle.
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    Code:
    struct ship
    {
           char name[20];
           int hull;
           int shields;
           int torp_str;
           int phaser_str;
    } standard, current, created;;
    
    
    standard.name = "Standard"; //error occurs on this line
    standard.hull = 100;        //this line
    standard.shields = 100;     //and this one
    standard.torp_str = 20;     //this one....
    standard.phaser_str = 40;   //and finally this one
    There's the code of the structure and the declarations. The error displayed is this:
    Code:
    expected constructor, destructor, or type conversion before '.' token
    and this
    Code:
    expected `,' or `;' before '.' token
    at the four lines that are commented.

    I don't understand though why strcpy() would work any better than just what I have for the character array since with non-structured variables you can store words in them in the same manner.

  5. #5
    and the hat of wrongness Salem's Avatar
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    It would seem to me that all your assignments are outside of a function.

    If you want to initialise your struct, do it like this.
    Code:
    struct ship standard = {
      "Standard",
      100,
      100,
      20,
      40
    };
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    Okay, I'll try that, but to change just a single variable, would I just use my previous code or would I have to do something else?

  7. #7
    C++まいる!Cをこわせ! Elysia's Avatar
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    That code creates a new struct named standard and initializes it to the given values. There's no such thing as a global structure initalization.

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    Okay, thanks all. It's working now... now I have yet to figure out another problem

  9. #9
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    Quote Originally Posted by teck View Post
    Okay, thanks all. It's working now... now I have yet to figure out another problem
    Ain't that always the way [Just got that myself - I got past one point, only to find that the code deadlocks because an interface I'm calling is calling back into the module I'm using, which has locks to prevent it from being re-entered, so the whole thing just sits there waiting ... ]

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    C++まいる!Cをこわせ! Elysia's Avatar
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    Ahh, the wonders of deadlocks and faulty locking. Multi-threading issues are so fun, aren't they?
    Well, suppose it's life. No one can escape small mistakes and bugs. Find that bug, matsp, I'm sure you can, and squish it! Good luck.

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    Quote Originally Posted by Elysia View Post
    Ahh, the wonders of deadlocks and faulty locking. Multi-threading issues are so fun, aren't they?
    Well, suppose it's life. No one can escape small mistakes and bugs. Find that bug, matsp, I'm sure you can, and squish it! Good luck.
    Yes, I know the solution (the code is attempting to initialize the module I'm calling from, which has already been initialized anyways, so we just need a "is this initialized" function), but in a large project you can't just go implement things in any file just willy-nilly - so I've worked around it for the moment by commenting the code out, until we have a proper function for asking if it's initialized. On to the next problem.

    Edit: and I prefer deadlocks from "strange things happen sometimes because two threads are trying to update the same data structure at the same time"....

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  12. #12
    C++まいる!Cをこわせ! Elysia's Avatar
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    Yes, I know what you mean. Been there, done that... infuriating, and usually hard to track down.

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    .... so I've worked around it for the moment by commenting the code out,....
    Yes the code I'm working on at work has many many green lines and blocks of green lines. I changed a lot but could not get it done in time to submit to source control. So I commented out all my new stuff and uncommented the old.

    I rarely erase anything until I know for sure I don't need it...and someone else doesn't need it.

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    Lol, although, fortunately for me though, my problem seemed to be easier than yours

    But still, while we are off topic, does anyone have any ideas how one would (with Dev-C++) manually (as in, in the actual code) link a library?

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    Ehm, what do you "manually, as in the code"?

    You can add "-lsomename" to the linker configuarion, to link in "somename.lib", does that help?

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    Compilers can produce warnings - make the compiler programmers happy: Use them!
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