c++ - Not able to read whole file -

i'm making c++ program able open .bmp image , being able put in 2d array. right have code this:

#include <iostream> #include <fstream> #include <sstream> #include <string> #include "image.h" using namespace std;  struct colour{     int red;     int green;     int blue; };  image::image(string location){      fstream stream;     string tempstr;      stringstream strstr;     stream.open(location);      string completestr;      while(!stream.eof()){         getline(stream, tempstr);         completestr.append(tempstr);     }     cout << endl << completestr;      image::length = completestr[0x13]*256 + completestr[0x12];     image::width = completestr[0x17]*256 + completestr[0x16];     cout << image::length;     cout << image::width;     cout << completestr.length();      int hexint;     int x = 0x36;     while(x < completestr.length()){         strstr << noskipws << completestr[x];         cout << x << ": ";         hexint = strstr.get();         cout << hex << hexint << " ";         if((x + 1)%3 == 0){             cout << endl;         }         x++;     } } 

now if run on test file of 256x256 print fine, until reaches 0x36e gives error / doesn't go further. happens because completestr string doesn't recieve data in bmp file. why isn't able read lines in bmp file?

there number of problems code. principal 1 (and reason problem) opening file in text mode. technically, means if file contains printable characters , few specific control characters (like '\t'), have undefined behavior. in practice, under windows, means sequences of 0x0d, 0x0a converted single '\n', , 0x1a interpreted end of file. not 1 wants when reading binary data. should open stream in binary mode (std::ios_base::binary).

not serious error, shouldn't use fstream if going read file. in fact, using fstream should rare: should use either ifstream or ofstream. same thing holds stringstream (but don't see role stringstream when reading binary file).

also (and real error), using results of getline without checking whether succeeded. usual idiom reading lines be:

while ( std::getline( source, ling ) ) ... 

but stringstream, don't want use getline on binary stream; remove of '\n' (which have been mapped crlf).

if want of data in memory, simplest solution like:

std::ifstream source( location.c_str(), std::ios_base::binary ); if ( !source.is_open() ) {     //  error handling... } std::vector<char> image( (std::istreambuf_iterator<char>( source ) ),                          (std::istreambuf_iterator<char>()) );