Difference between typdefing and declaring structs

This is a discussion on Difference between typdefing and declaring structs within the C++ Programming forums, part of the General Programming Boards category; What's the difference between this: Code: struct aStruct { int aNumber; }; and Code: typedef struct { int aNumber; } ...

  1. #1
    myNegReal
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    Jun 2005
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    Difference between typdefing and declaring structs

    What's the difference between this:
    Code:
    struct aStruct {
           int aNumber;
    };
    and
    Code:
    typedef struct {
          int aNumber;
    } aStruct;
    All I can think of is maybe the compiler will replace aStruct with the actual struct{} definition with typedef?
    Using Dev-C++ on Windows

  2. #2
    Banned
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    Jun 2005
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    this might explain what you are wondering

    http://msdn.microsoft.com/library/de...m/tions_14.asp

  3. #3
    *this
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    I think that the typedef is common in C so you dont have to type struct each time you declared an object (or use one) of that structure. But essentially they are the same thing.

    so you dont have to do:
    Code:
    struct Foo {
       int a, b;
    };
    
    int main () {
       struct Foo testData;
    }
    Instead you can do...
    Code:
    typedef struct {
       int a, b;
    } Foo;
    
    int main () {
       Foo testData;
    }
    It's usefull in C because you must specify a struct with "struct" even when declaring or passing the struct, so the client doesn't need to know that Foo is a structure.
    Last edited by JoshR; 07-21-2005 at 12:06 AM.

  4. #4
    myNegReal
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    So really it has no difference in C++, just C?
    Using Dev-C++ on Windows

  5. #5
    *this
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    Quote Originally Posted by Ganoosh
    So really it has no difference in C++, just C?
    Correct. They are the same thing, its just in C you have to use the word "struct" before all variables of a structure. A typedef is a way to get around that.

  6. #6
    myNegReal
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    Jun 2005
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    I see
    Using Dev-C++ on Windows

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