namespace question

**Dave++** · 06-01-2007

Mario, this is about a 2002 thread...

I'm currently compiling code on a linux box and running into namespace problems.
As I go through the permutations of namespace combinations I'm able to mimic much of the action discussed here and in other threads.

In the beginning all my classes were saying "...expected...before...token"
Then I took out the namespace std and this helped because then I was able to see THAT my classes were suffering from the same types of problems.

So, I was able to solve half the problems dealing with scope by playing with namespace, etc.
BUT, the classes are still not working.
The example below is a mix of std:: and not std:: to see what happens. I can add std:: to every call but what can make my classes work?

Thanks 10^6
Dave
PS - I'm coding this summer...this never happened in C
Will "namespaces" ultimately kill C++ ?

It's all in progress...but I've clipped the larger code down to bare bones for testing.
Thanks for the help in advance (begging by any other cleche)

Code:

cat -n Vtest.h (clipped)
     4  // The routines will initially return text messages for debugging and then later be overloaded for data
     5
     6  #include <iostream>
     7  #include <fstream>
     8  #include <stdio.h>
     9  #include <time.h>
    10  #include <math.h>
    11
    12  #include <usb.h>
    13  #include <libxxusb.h>
    14
    15  class vtest 
    16     {
    17     private:
    18      usb_dev_handle *udev;     // Device Handle 
    19      char scalerChar[20];
    20      long value;
    21     public:
    22      int icount;
    23      vtest(usb_dev_handle *udev);
    24      void vtestvoid(long &value);
    25      long vtestlong(long &value);
    26      char vtestchar(long &value);
    27      int vtestcount(int icount);
    28      int vtestvalue(void);
    29     };
    30
    31  vtest::vtest(usb_dev_handle *udev){
    32    icount = 0;
    33    value = 90:
    34  }
    35
    36  vtest::vtestvoid(&value){
    37    value = 98;
    38  }
    39
    40  vtest::vtestlong(&value){
    41    value = 99;
    42    return(value);
    43  }

cat -n Vtest.cpp (clipped)
     5  #include <iostream>
     6  #include <fstream>
     7  #include "Vtest.h"   // case sensetive
     8
     9  std::cout cout;
    10  std::endl endl;
    11
    12  int CheckDevice(usb_dev_handle *udev){ //Check if device is open. If not, end program
    13      if(udev)
    14         {
    15         cout << "VM-USB device is open for communication" << endl;
    16         }
    17      else
    18         {
    19         cout << "No VM-USB devices found!" << endl;
    20         // fout << "No VM-USB devices found!" << endl; // send a message to the log file?
    21         return 0;   // won't end the program but useful to if()
    22         }
    23  }
    24
    25  int main ()
    26  {
    27      // initialize
    28      char logName[79];
    29      long value;
    30
    31      xxusb_device_type devices[99]; 
    32      struct usb_device *dev;
    33      usb_dev_handle *udev;       // Device Handle 
    34
    35      //Find XX_USB devices and open the first one found
    36      xxusb_devices_find(devices);
    37      dev = devices[0].usbdev;
    38      udev = xxusb_device_open(dev); 
    39      
    40      std::cout << "Trying to establish communication with the VM-USB" << std::endl;
    41   
    42      if (!CheckDevice(udev)) return 0;
 
In file included from Vtest.cpp:7:
Vtest.h: In constructor `vtest::vtest(usb_dev_handle*)':
Vtest.h:33: error: expected `;' before ':' token
Vtest.h: At global scope:
Vtest.h:36: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:36: error: expected `,' or `;' before '(' token
Vtest.h:40: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:40: error: expected `,' or `;' before '(' token
Vtest.h:45: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:45: error: expected `,' or `;' before '(' token
Vtest.h:51: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:51: error: expected `,' or `;' before '(' token
Vtest.h:56: error: ISO C++ forbids declaration of `vtestvalue' with no type
Vtest.cpp:9: error: expected constructor, destructor, or type conversion before "cout"
Vtest.cpp:9: error: expected `,' or `;' before "cout"
Vtest.cpp:10: error: expected constructor, destructor, or type conversion before "endl"
Vtest.cpp:10: error: expected `,' or `;' before "endl"
Vtest.cpp: In function `int CheckDevice(usb_dev_handle*)':
Vtest.cpp:15: error: `cout' undeclared (first use this function)
Vtest.cpp:15: error: (Each undeclared identifier is reported only once for each function it appears in.)
Vtest.cpp:15: error: `endl' undeclared (first use this function)
make: *** [Vtest] Error 1

Makefile (clipped)
     3  .LIBPATTERNS    ="'lib&#37;.so lib%.a' "
     4
     5  VERBOSE         = 1
     6
     7  CXX             = g++ -v -g
     8
     9  RM              = rm *~
    10
    11  LD              = gcc-3.3
    12  LDFLAGS         = -O
    13  SOFLAGS         = -shared
    14
    15  CXXLIBDIRS      = -l /usr/include/lib/
    16  CXXLIBS         = -l xx_usb
    17  INCLUDEDIRS     = -I .
    18
    19  CXXFLAGS        = -O -Wall -fPIC -g $(INCLUDEDIRS)
    20
    21  LDFLAGS         = $(CXXFLAGS)
    22
    23  OBJ = Vtest.exe
    24
    25  Vtest: 
    26          $(CXX) $(CXXFLAGS) \
    27          $(CXXLIBS) $(CXXLIBDIRS) -o $(OBJ) Vtest.cpp
    28          @echo "Done"

**Daved** · 06-01-2007

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Note that one of the rules here is to not bump old threads. Five years is pretty old. A better choice would be to create a new thread and link to one if you think it is pertinent.

Your biggest problem doesn't appear to have anything to do with namespaces. On line 33 of vtest.h you have a colon : instead of a semicolon ;.

In addition,

Code:

std::cout cout;

is incorrect syntax. I assume you meant:

Code:

using std::cout;

although I prefer to just use std::cout everywhere instead of the using directive or declaration.

**Salem** · 06-01-2007

Split from http://cboard.cprogramming.com/showthread.php?t=19011

**Dave++** · 06-03-2007

Daved, Thanks for the response and feedback. I originally posted with out the "code" tags.

Regretablly, the compiller persists in its error and after a week of trying to weed it out I did seem to boil it down to some type of workspace issue.

> So, I was able to solve half the problems dealing with scope by playing with namespace, etc.
> BUT, the classes are still not working.

Could it be the compiler and the makefile?

Code:

In file included from Vtest.cpp:7:
Vtest.h:36: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:36: error: expected `,' or `;' before '(' token
Vtest.h:40: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:40: error: expected `,' or `;' before '(' token
Vtest.h:45: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:45: error: expected `,' or `;' before '(' token
Vtest.h:51: error: expected constructor, destructor, or type conversion before '(' token
Vtest.h:51: error: expected `,' or `;' before '(' token
Vtest.h:56: error: ISO C++ forbids declaration of `vtestvalue' with no type

I know its an easy one...and after googling for days I've seen others say "solved" but no one actually said "how..."

Regards,
Dave

**Dave_Sinkula** · 06-03-2007

Shot in the dark:

Code:

vtest::vtest(usb_dev_handle *udev){
  icount = 0;
  value = 90:
}

vtest::vtestvoid(&value){
  value = 98;
}

vtest::vtestlong(&value){
  value = 99;
  return(value);
}

Perhaps the last two are missing a type, not to mention a return type?

**Dave++** · 06-04-2007

Thanks Dave,
Yes, I realized that my format in the header file was screwed up late last night.
In the old days I'd just search for zeros and ohs or lines longer that the card could take.

Code:

// example: class constructor
#include <iostream>
using namespace std;

class CRectangle {
    int width, height;
  public:
    CRectangle (int,int);
    int area () {return (width*height);}
};

CRectangle::CRectangle (int a, int b) {
  width = a;
  height = b;
}

int main () {
  CRectangle rect (3,4);
  CRectangle rectb (5,6);
  cout << "rect area: " << rect.area() << endl;
  cout << "rectb area: " << rectb.area() << endl;
  return 0;
}

Thanks for the help. This is one of those 2x4 problems.

Dave

**Dave_Sinkula** · 06-04-2007

Originally Posted by Dave++

Code:

CRectangle::CRectangle (int a, int b) {
  width = a;
  height = b;
}

FWIW, consider using initialization lists

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