Question

I am using Borland Builder C++. I have a memory leak and I know it must be because of this class I created, but I am not sure how to fix it. Please look at my code– any ideas would be greatly appreciated!

Here’s the .h file:

#ifndef HeaderH #define HeaderH #include <vcl.h> #include <string> using std::string; class Header {   public:     //File Header     char FileTitle[31];     char OriginatorName[16];      //Image Header     char ImageDateTime[15];     char ImageCordsRep[2];     char ImageGeoLocation[61];      NitfHeader(double latitude, double longitude, double altitude, double heading);     ~NitfHeader();     void SetHeader(char * date, char * time, double location[4][2]);      private:      void ConvertToDegMinSec (double angle, AnsiString & s, bool IsLongitude);     AnsiString ImageDate;     AnsiString ImageTime;     AnsiString Latitude_d;     AnsiString Longitude_d;     double Latitude;     double Longitude;     double Heading;     double Altitude;  }; 

And here is some of the .cpp file:

void Header::SetHeader(char * date, char * time, double location[4][2]){     //File Header strcpy(FileTitle,'Cannon Powershot A640'); strcpy(OperatorName,'Camera Operator');     //Image Header //Image Date and Time    ImageDate = AnsiString(date);    ImageTime = AnsiString(time);    AnsiString secstr = AnsiString(ImageTime.SubString(7,2));    AnsiString rounder = AnsiString(ImageDate.SubString(10,1));    int seconds = secstr.ToInt();     //Round off seconds  - will this be necessary with format hh:mm:ss in text file?    if (rounder.ToInt() > 4) {      seconds++;     }    AnsiString dateTime = ImageDate.SubString(7,4)+ ImageDate.SubString(4,2) + ImageDate.SubString(1,2) + ImageTime.SubString(1,2)                     + ImageTime.SubString(4,2) + AnsiString(seconds);    strcpy(ImageDateTime,dateTime.c_str());     //Image Coordinates Representation    strcpy(ImageCordsRep,'G');     //Image Geographic Location    AnsiString lat;    AnsiString lon;    AnsiString locationlat_d;    AnsiString locationlon_d;    AnsiString corner;     for (int i = 0; i < 4; i++){       ConvertToDegMinSec(location[i][0],lat,false);      ConvertToDegMinSec(location[i][1],lon,true);       if(location[i][0] < 0){         locationlat_d = 'S';         ConvertToDegMinSec(-location[i][0],lat,false);       }else if(location[i][0] > 0){         locationlat_d = 'N';      }else locationlat_d = ' ';       if(location[i][1] < 0){         locationlon_d = 'W';         ConvertToDegMinSec(-location[i][1],lon,true);      }else if(location[i][1] > 0){          locationlon_d = 'E';      }else locationlon_d = ' ';       corner += lat + locationlat_d + lon + locationlon_d;     }    strcpy(ImageGeoLocation,corner.c_str());  }   

Now when I use the class in main, basically I just create a pointer:

Header * header = new Header; header->SetHeader(t[5],t[6],corners->location); char * imageLocation = header->ImageGeoLocation; //do something with imageLocation delete header; 

Where corners->location is a string from another class, and t[5] and t[6] are both strings. The problem is that imageLocation doesn’t contain what is expected, and often just garbage. I have read a lot about memory leaks and pointers, but I am still very new to programming and some of it is quite confusing. Any suggestions would be fabulous!!

Answer 1

I’m afraid there are a number of issues here.

For starters char ImageCordsRep[1]; doesn’t work … a string is always null terminated, so when you do strcpy(ImageCordsRep,'G'); you are overflowing the buffer.

It would also be good practice to terminate all those string buffers with a null in your constructor, so they are always valid strings.

Even better would be to use a string class instead of the char arrays, or at least use ‘strncpy’ to prevent buffer overruns if the incoming strings are larger than you expect.