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#ifndef

hannes (97)
What is wrong with the following lines of code?
the header file is called: vergelijking.h
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#ifdef VERGELIJKING_H_
#define VERGELIJKING_H_
#endif

chrisname (7395)
You're putting #ifdef not #ifndef
So if VERGELIJKING_H_ is defined, you're defining it again.

I think you can use
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#pragma once

// Header code

which should yield faster compile times. It won't be noticeable in small projects.

You can even combine the two:

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#pragma once
#ifndef _MYHEADER_H_
#define_MYHEADER_H_
// Header code
#endif
Last edited on
hannes (97)
it doesn't works too
chrisname (7395)
What doesn't? I told you three things:
#pragma once
#if
and combining the two.

What are you trying to do? Let me see the full header code.
hannes (97)
ok, here you are:
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#pragma once
#ifndef VERGELIJKING_H_
#define VERGELIJKING_H_


//#include "handige_functies.h"

class berekening{
      protected:
              float beginmaat, eindmaat, uitkomst;//ok
              char maten[15][15];//ok
              float *eenheden;//ok
              int aantalp;//ok
      public:
              bool checken(char *cbegin, char *ceind);//ok
              void berekenen(float beginhoeveel);//de uitkomst berekenen: ok
              float getuitkomst();//de uitkomst returnen :ok
              };//end class



//______________________________________________________________________________
void berekening::berekenen(float beginhoeveel)
{
     //berekenen
     uitkomst = (beginmaat / eindmaat) * beginhoeveel;
}//end function
//______________________________________________________________________________
float berekening::getuitkomst()
{
      return uitkomst;
}
//______________________________________________________________________________
bool berekening::checken(char *cbegin, char *ceind)
{
     int count=0;
     bool check=false, beind=false, bbegin=false;
     for(count=0; count<aantalp; count++)
     {
          if(strcmp(cbegin, maten[count])==0)
          {
               bbegin=true;
               beginmaat=eenheden[count];
          }//end if
          else{bbegin=false;}
          if(strcmp(ceind, maten[count])==0)
          {
               beind=true;
               eindmaat=eenheden[count];
          }
          else{beind=false;}//end if
     }//next count

     if(bbegin==true && beind==true)
     {
          check=true;
     }
     return check;
}//end function
/*______________________________________________________________________________
________________________________________________________________________________
______________________________________________________________________________*/
class Lengte: public berekening{
      public:
              Lengte();//constructor
              };//end class

Lengte::Lengte()
{
     strcpy(maten[0],"mm");
     strcpy(maten[1],"cm");
     strcpy(maten[2],"inch");
     strcpy(maten[3],"dm");
     strcpy(maten[4],"chain");
     strcpy(maten[5],"foot");
     strcpy(maten[6],"yard");
     strcpy(maten[7],"m");
     strcpy(maten[8],"dam");
     strcpy(maten[9],"hm");
     strcpy(maten[10],"km");
     strcpy(maten[11],"mile");

     eenheden=new float[12];
     eenheden[0]=0.001;
     eenheden[1]=0.01;
     eenheden[2]=0.0254;
     eenheden[3]=0.1;
     eenheden[4]=0.201168;
     eenheden[5]=0.3048;
     eenheden[6]=9144;
     eenheden[7]=1;
     eenheden[8]=10;
     eenheden[9]=100;
     eenheden[10]=1000;
     eenheden[11]=1609.344;

     aantalp=11;
     beginmaat=0;
     eindmaat=0;
     uitkomst=0;
}//end constructor
#endif

helios (17574)
What exactly is the point of using both #pragma one and inclusion guards?
hannes (97)
who are you asking?
chrisname (7395)
I see no reason why the preprocessor includes are not working.

It does not work for me, either...

I didn't say there was a point in doing it, I was saying it was possible.

I think the point is because it's faster on some compilers to use #pragma once. But then that would be lost because you're using #endif anyway... I'm not sure.
Last edited on
helios (17574)
who are you asking?
It's an open semi-rhetorical question.

I was saying it was possible
It's also possible to assign something to itself. It doesn't mean there's a point to it.
chrisname (7395)
My point was that there may not be a point to it.
helios (17574)
Mine was that whether something is possible or not is irrelevant if there's no point in doing it.
chrisname (7395)
Ok, then.

Any idea on the problem itself, because I have none :(
helios (17574)
OP is doing it wrong.
closed account (z05DSL3A)
With #pragma once, if a file gets included a lot of times, it is only processed once.
With #ifndef ..., the file would have to be loaded and processed each time it is included.

#pragma once is an MS thing, so the backup #ifndef ... is recommended if you are sharing.
Duthomhas (13206)
@hannes

You must split your file into two separate files.

vergelijking.hpp 
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#pragma once
#ifndef VERGELIJKING_H_
#define VERGELIJKING_H_

class berekening{
      protected:
              float beginmaat, eindmaat, uitkomst;//ok
              char maten[15][15];//ok
              float *eenheden;//ok
              int aantalp;//ok
      public:
              bool checken(char *cbegin, char *ceind);//ok
              void berekenen(float beginhoeveel);//de uitkomst berekenen: ok
              float getuitkomst();//de uitkomst returnen :ok
};//end class

//______________________________________________________________________________
class Lengte: public berekening{
      public:
              Lengte();//constructor
};//end class

#endif

vergelijking.cpp 
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#include "vergelijking.hpp"

//______________________________________________________________________________
void berekening::berekenen(float beginhoeveel)
{
     //berekenen
     uitkomst = (beginmaat / eindmaat) * beginhoeveel;
}//end function
//______________________________________________________________________________
float berekening::getuitkomst()
{
      return uitkomst;
}
//______________________________________________________________________________
bool berekening::checken(char *cbegin, char *ceind)
{
     int count=0;
     bool check=false, beind=false, bbegin=false;
     for(count=0; count<aantalp; count++)
     {
          if(strcmp(cbegin, maten[count])==0)
          {
               bbegin=true;
               beginmaat=eenheden[count];
          }//end if
          else{bbegin=false;}
          if(strcmp(ceind, maten[count])==0)
          {
               beind=true;
               eindmaat=eenheden[count];
          }
          else{beind=false;}//end if
     }//next count

     if(bbegin==true && beind==true)
     {
          check=true;
     }
     return check;
}//end function
/*______________________________________________________________________________
________________________________________________________________________________
______________________________________________________________________________*/
Lengte::Lengte()
{
     strcpy(maten[0],"mm");
     strcpy(maten[1],"cm");
     strcpy(maten[2],"inch");
     strcpy(maten[3],"dm");
     strcpy(maten[4],"chain");
     strcpy(maten[5],"foot");
     strcpy(maten[6],"yard");
     strcpy(maten[7],"m");
     strcpy(maten[8],"dam");
     strcpy(maten[9],"hm");
     strcpy(maten[10],"km");
     strcpy(maten[11],"mile");

     eenheden=new float[12];
     eenheden[0]=0.001;
     eenheden[1]=0.01;
     eenheden[2]=0.0254;
     eenheden[3]=0.1;
     eenheden[4]=0.201168;
     eenheden[5]=0.3048;
     eenheden[6]=9144;
     eenheden[7]=1;
     eenheden[8]=10;
     eenheden[9]=100;
     eenheden[10]=1000;
     eenheden[11]=1609.344;

     aantalp=11;
     beginmaat=0;
     eindmaat=0;
     uitkomst=0;
}//end constructor

Good luck!
Last edited on
hannes (97)
it was a fault with my environment. anyway, many thanks!
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