how t properly pass a struct into a funct

This is a discussion on how t properly pass a struct into a funct within the C Programming forums, part of the General Programming Boards category; Before I get into anymore bad habits, please help me with passing a struct into a function. I've never had ...

  1. #1
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    how t properly pass a struct into a funct

    Before I get into anymore bad habits, please help me with passing a struct into a function. I've never had the need to do this in the past, but it seems like I need it now. If I had a struct like

    Code:
    struct test
    {
        int a, b, c, d , e;
    
        char name1[20];
        char name2[20];
    
        ......
    };
    How exactly I would I write the prototype, definition, and caller? I would want to have several functions have access to the same data set.

    TIA
    I haven't used a compiler in ages, so please be gentle as I try to reacclimate myself. :P

  2. #2
    moi
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    Registered User moi's Avatar
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    i *think*

    Code:
    struct test
    {
        int a, b, c, d , e;
        char name1[20];
        char name2[20];
    };
    
    // prototype
    
    void structfunc (struct test t);
    
    // pass
    
    struct test q;
    structfunc (q);
    
    // function
    
    void structfunc (struct test t)
    {
      t.a += 4;
      t.name1[6] = 'Q';
    }
    i use typedef struct normally which has a few subtle differences from struct, and i think i remembered them here, but not sure

    edit: obviously this leads out stupid stuff like putting useful data in q before calling structfunc()
    hello, internet!

  3. #3
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    Hey thanks for the reply moi.... I'll give this a shot.
    I haven't used a compiler in ages, so please be gentle as I try to reacclimate myself. :P

  4. #4
    Code Goddess Prelude's Avatar
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    It's almost always better to pass a pointer to the structure instead of passing the structure itself. This way you don't waste memory by copying the structure, all you copy is a pointer.

    -Prelude
    My best code is written with the delete key.

  5. #5
    and the hat of wrongness Salem's Avatar
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    > It's almost always better to pass a pointer to the structure
    Best make sure it's a pointer to a const structure, just in case you accidentally try and modify it.

    > i use typedef struct normally which has a few subtle differences from struct
    The only difference is you don't have to keep saying struct. Apart from that, the typedef of a struct is exactly the same as the struct.

  6. #6
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    The pointer sounds like a plan. Thanks to all.
    I haven't used a compiler in ages, so please be gentle as I try to reacclimate myself. :P

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