Thread: Global Class problem

If "InputQueue_c InputQueue; " is outside int main ,being declared as global, the code will compile but it will trigger a memory error and crash. if "InputQueue_c InputQueue; " is inside int main() it works fine, or so it seems. What am i doing wrong?

Code:

#include <iostream>
#include <windows.h>
using namespace std;
struct Queue_str
{ int iFlag;
  void * info;
  int iFrom;
  int iTo; 
  Queue_str * next; 
       
       };
struct Data_str
{ int iFlag;
  void * info;
  int  iFrom;
  int  iTo; 
  
       };
       
Data_str * CreateData(void * pArg, int iFlag, int iFrom, int iTo)
{Data_str * strData;
 strData=new Data_str;
 strData->info=pArg;
 strData->iFlag=iFlag;
 strData->iFrom=iFrom;
 strData->iTo=iTo;
   return strData;
         };



class InputQueue_c
{public:
   int iCount;
   Queue_str * pLastRead;
   Queue_str * pStart;
   Queue_str * pEnd;
   
         
        void Input(Data_str * strData) {
             
             pEnd->next=new Queue_str;
             pEnd->next->info=strData->info;
             pEnd->next->iFlag=strData->iFlag;
            
             pEnd->next->iFrom=strData->iFrom;             
             pEnd->next->iTo=strData->iTo;
             
             pEnd->next->next=NULL;
             pEnd=pEnd->next;
             iCount++;
            
             } 
        Data_str *  Read()
        {   Data_str * strData;
           strData=new Data_str;
            
            if (pLastRead==pEnd)
           {strData->info=(void*) "\0";
            strData->iFlag=-1;
            return strData;
               }
            
        Queue_str *pBuffer;
          pBuffer=pLastRead->next;
          pLastRead=pBuffer;
          strData->iFlag=pBuffer->iFlag;
          strData->info=pBuffer->info;
          strData->iFrom=pBuffer->iFrom;
          strData->iTo=pBuffer->iTo;
          return strData;
             
             }
          bool Unread() {if(pEnd==pLastRead) return 0;
                       else return 1;
            }   
        InputQueue_c(){iCount=0; pLastRead=pStart; pEnd=pStart; }
       ~InputQueue_c(){} 
      };
      

  InputQueue_c InputQueue;  
int main()

{   
     InputQueue.Input(CreateData((void*)"test",1, 0,0 )) ; //at this point it will crash
    cout<<(char*)InputQueue.Read()->info;
cin.get();
    
    }

Try initializing pStart. That it's working when it's a stack variable... I think you're just getting lucky.

thanks, i should be more careful.