functions

This is a discussion on functions within the C++ Programming forums, part of the General Programming Boards category; "Write the definition of a function that takes such a pointer as an argument and returns its argument as the ...

  1. #1
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    May 2006
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    functions

    "Write the definition of a function that takes such a pointer as an argument and returns its argument as the return value."

    Code:
    // decs2.cc
    int main() {
     
      void f1(char*, int&);
      void (*pf1)(char*, int&);
    
      typedef void (*PF1) (char*, int&);
      typedef void (*PF1_ARG) (char*, int&);
    
      PF1 rp_pf1(PF1_ARG a) { // no good
         return a;
      }
    
    
    
    }
    Output:
    Code:
    decs2.cc: In function `int main()':
    decs2.cc:11: syntax error before `{' token
    Thanks.

  2. #2
    C++まいる!Cをこわせ! Elysia's Avatar
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    22,765
    Why the complication? Use a normal pointer like int* or something.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  3. #3
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    Oops, sorry.

    The "such a pointer" is

    "a pointer to a function taking arguments of type pointer to character and reference to integer and returning no value"

    which is a

    Code:
    void (*pf) (char*, int&)

    I think...

  4. #4
    C++まいる!Cをこわせ! Elysia's Avatar
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    Your code is basically right, but nested functions are undefined. Move it outside main.
    Code:
    typedef void (MyFunctionPtr)(char*, int&);
    
    MyFunctionPtr* Help2(MyFunctionPtr* p)
    {
    	return p;
    }
    
    void Help3(char* p, int& n)
    {
    }
    
    int main()
    {
    	Help2(&Help3);
    	return 0;
    }
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  5. #5
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    Join Date
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    Your code is basically right, but nested functions are undefined.
    Oh.

    Thanks! It's working fine now.

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