struct in function

This is a discussion on struct in function within the C++ Programming forums, part of the General Programming Boards category; I made this script to start a program: Code: #include <iostream.h> #include <windows.h> using namespace std; struct exec { char ...

  1. #1
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    struct in function

    I made this script to start a program:

    Code:
    #include <iostream.h>
    #include <windows.h>
    
    using namespace std;
    
    struct exec
    {
      char path[];
      char par[];
      char dir[];
    };
    
    void execute (exec *x)
    {
    
      HINSTANCE hRet = ShellExecute(
        HWND_DESKTOP, //Parent window
        "open",       //Operation to perform
        x->path,       //Path to program
        x->par,         //Parameters
        x->dir,         //Default directory
        SW_SHOW);     //How to open
    
      if((LONG)hRet <= 32)
      {
        cout << "Wrong directory!!" << endl;
      }
    }
    
    int main()
    {
      cout << "Starting firefox..." << endl;
      exec pars = {"C:\\Program Files\\Mozilla Firefox\\firefox.exe", "", ""};
      execute(&pars);
      system("PAUSE");
    
      return 0;
    }
    No errors (Win XP, Borland), but when I execute the file, it couts:
    "Wrong directory!". What am I doing wrong??
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  2. #2
    Devil's Advocate SlyMaelstrom's Avatar
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    Couldn't tell you. Works fine for me.

    The only thing I'd say is, why use the std namespace if you're using depreciated libraries? And why not use the std::string object instead of character arrays? My compiler had problems until I changed it to strings.

    And lastly, don't call it a script, call it source code. C++ is not a scripting language.
    Last edited by SlyMaelstrom; 03-02-2006 at 12:12 PM.
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  3. #3
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    22 errors!

    I think ShellExecute() only accepts C strings?
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  4. #4
    Devil's Advocate SlyMaelstrom's Avatar
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    Ofcourse it does, which is why you'd want to call the c_str() function on your std::string objects.

    Code:
      HINSTANCE hRet = ShellExecute(
        HWND_DESKTOP, //Parent window
        "open",       //Operation to perform
        x->path.c_str(),       //Path to program
        x->par.c_str(),         //Parameters
        x->dir.c_str(),         //Default directory
        SW_SHOW);     //How to open
    
      if((LONG)hRet <= 32)
      {
        cout << "Wrong directory!!" << endl;
      }
    By the way, if I had to guess. I'd say your problem lies with the fact that you're casting to a LONG not a long and your compiler might not like that, but I could be wrong.
    Last edited by SlyMaelstrom; 03-02-2006 at 12:12 PM.
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  5. #5
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    Thx for replying! I did it like this:

    Code:
    #include <iostream.h>
    #include <windows.h>
    
    using namespace std;
    
    struct exec
    {
      string path;
      string par;
      string dir;
    };
    
    void execute (exec *x)
    {
    
      HINSTANCE hRet = ShellExecute(
        HWND_DESKTOP, //Parent window
        "open",       //Operation to perform
        x->path.c_str(),       //Path to program
        x->par.c_str(),         //Parameters
        x->dir.c_str(),         //Default directory
        SW_SHOW);     //How to open
    
      if((long)hRet <= 32)
      {
        cout << "Wrong directory!!" << endl;
      }
    }
    
    int main()
    {
      cout << "Starting firefox..." << endl;
      exec pars;
      pars.path = "C:\\Program Files\\Mozilla Firefox\\firefox.exe";
      execute(&pars);
      system("PAUSE");
    
      return 0;
    }
    It didn't accept
    Code:
    exec pars = {"C:\\Program Files\\Mozilla Firefox\\firefox.exe", "", ""};
    so I changed it to
    Code:
    pars.path = "C:\\Program Files\\Mozilla Firefox\\firefox.exe";
    Is there a better/faster way to do that?
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  6. #6
    erstwhile
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    If by 'faster' you mean essentially to declare and set the struct members in a single line then give it a constructor taking 3 strings, eg
    Code:
    #include <iostream>
    #include <windows.h>
    
    using namespace std;
    
    struct exec
    {
      string path;
      string par;
      string dir;
      
      exec(){};
      exec(const string& p,const string& a,const string& d):path(p),par(a),dir(d){}
    };
    
    
    void execute (exec *x)
    {
    
      HINSTANCE hRet = ShellExecute(
        HWND_DESKTOP, //Parent window
        "open",       //Operation to perform
        x->path.c_str(),       //Path to program
        x->par.c_str(),         //Parameters
        x->dir.c_str(),         //Default directory
        SW_SHOW);     //How to open
    
      if((long)hRet <= 32)
      {
        cout << "Wrong directory!!" << endl;
      }
    }
    
    int main()
    {
      cout << "Starting firefox..." << endl;
      exec pars("C:\\Program Files\\Mozilla Firefox\\firefox.exe","","");
      //pars.path = "C:\\Program Files\\Mozilla Firefox\\firefox.exe";
      execute(&pars);
      system("PAUSE");
    
      return 0;
    }
    And use <iostream>, not <iostream.h> as SlyMaelstrom suggested.
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  7. #7
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    Can you give an explanation about

    Code:
      exec(){};
      exec(const string& p,const string& a,const string& d):path(p),par(a),dir(d){}
    I haven't examined constructors yet.
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  8. #8
    Devil's Advocate SlyMaelstrom's Avatar
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    You have to include <string>. This compiles for me:
    Code:
    #include <iostream>
    #include <string>
    #include <windows.h>
    
    using namespace std;
    
    struct exec
    {
      string path;
      string par;
      string dir;
    };
    
    void execute (exec *x)
    {
    
      HINSTANCE hRet = ShellExecute(
        HWND_DESKTOP, //Parent window
        "open",       //Operation to perform
        x->path.c_str(),       //Path to program
        x->par.c_str(),         //Parameters
        x->dir.c_str(),         //Default directory
        SW_SHOW);     //How to open
    
      if((int)hRet <= 32)
      {
        cout << "Wrong directory!!" << endl;
      }
    }
    
    int main()
    {
      cout << "Starting firefox..." << endl;
      exec pars = {"C:\\Program Files\\Mozilla Firefox\\firefox.exe", "", ""};
      execute(&pars);
      system("PAUSE");
    
      return 0;
    }
    Sent from my iPadŽ

  9. #9
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    I use Borland compiler and it gives 16 errors
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  10. #10
    Devil's Advocate SlyMaelstrom's Avatar
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    Such as? I'm thinking about modern Borland compilers and 0 of them comes to mind.
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  11. #11
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    } expected in function main()

    cannot convert char* to exec

    Declaration missing ; in function main()

    Unexpected }

    Type name expected

    Illegal initialisation
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  12. #12
    Devil's Advocate SlyMaelstrom's Avatar
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    If I had to guess, it's because your compile is ancient and probably doesn't know std::string. This is also probably why you're still using old libraries.
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  13. #13
    erstwhile
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    Quote Originally Posted by SlyMaelstrom
    I'm thinking about modern Borland compilers and 0 of them comes to mind.
    Which versions are you referring to? Bcc v5.6.4(cbuilderx; I'm fairly certain this is the same version used by bcb6, too) gives the same errors with the same code as does bcc551(the version used by Ideswa) - which is partly why I made my earlier suggestion.
    Quote Originally Posted by SlyMaelstrom
    your compile is ancient
    That's a fair point - the compiler is getting old (2001/2002), so, perhaps, a change to a more modern compiler might not be a bad idea.
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  14. #14
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    >> why use the std namespace if you're using depreciated libraries?
    BTW, the word is deprecated (depreciated means something different), and <iostream.h> isn't deprecated anyway, it is completely non-standard.

  15. #15
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    I'm getting errors in source codes that compile excellent in Borland!
    I have to write them all over again!!!
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

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