Reading a binary file

// EXAMPLES




1. include <iostream>
2. include <fstream>

using namespace std;

int main(void) {

  const unsigned int Matrix_Rows = 256;
  const unsigned int Matrix_Cols = 256;
  unsigned char area_matrix[Matrix_Rows * Matrix_Cols];
  unsigned char pointers_matrix[Matrix_Rows][Matrix_Cols];
  ifstream data_file("filename", ios::binary);

  // Reading an area of bytes 
  data_file.read(area_matrix, sizeof(area_matrix));

  // Rewinding the input file 
  data_file.clear(); // just in case.
  data_file.seekg(0);

  // Reading a two-dimensional array of bytes 
  for (unsigned int i = 0; i < Matrix_Rows; ++i)
  {
    data_file.read(pointers_matrix[i],
                   Matrix_Cols);
  }

  return 0;

}

1. include &ltfstream>
2. include &ltctime>
3. include &ltstring>
4. include &ltvector>

using namespace std;

int main() {

 std::ifstream in("pp1.txt",std::ios::binary);
 if (!in)
 {
    std::cout << "problem with file open" << std::endl;
    return 0;
 }

 clock_t c1,c2;

 c1 = clock();

 in.seekg(0,std::ios::end);
 unsigned long length = in.tellg();
 in.seekg(0,std::ios::beg);

  vector< char > vTmp(length+1,0);
  in.read(&vTmp[0],length);

  string str;
  str.reserve(length);
  str.assign(&vTmp[0],&vTmp[0]+length); // no NULL at end
 

 c2 = clock();

 std::cout << static_cast< double >(c2-c1)/static_cast< double >(CLOCKS_PER_SEC) << std::endl;

 return 0;

}

directly into std::string

1. include &ltiostream>
2. include &ltfstream>
3. include &ltctime>
4. include &ltstring>

using namespace std;

int main() { std::ifstream in("pp1.txt",std::ios::binary); if (!in) { std::cout << "problem with file open" << std::endl; return 0; }

clock_t c1,c2;

c1 = clock();

in.seekg(0,std::ios::end); unsigned long length = in.tellg(); in.seekg(0,std::ios::beg);

string str(length,0); std::copy( std::istreambuf_iterator< char >(in) , std::istreambuf_iterator< char >() , str.begin() );

c2 = clock();

std::cout << static_cast< double >(c2-c1)/static_cast< double >(CLOCKS_PER_SEC) << std::endl;

return 0; }