string filename = "C:\\test.bin";
int value = 7;
#if USE_OFSTREAM_STUFF
ofstream outputFile;
outputFile.open( filename.c_str(), ios_base::out | ios_base::binary );
if ( outputFile.is_open() )
{
outputFile << value;
outputFile.close();
}
#else
FILE* outputFile;
outputFile = fopen( filename.c_str(), "wb" );
if ( outputFile )
{
fwrite( &value, sizeof(value), 1, outputFile );
fclose( outputFile );
}
#endif
STL file IO [Solved]
Author
Can anybody explain to me why the following code behaves differently depending on whether it's using the ofstream stuff, or old C-style FILE* stuff?
Rather than using
You can see that this corresponds much more closely to your "fwrite" call. Using the insertion operator ('<<') corresponds to using fprintf.
outputFile << value;outputFile.write(reinterpret_cast<char *>&value, sizeof(value));You can see that this corresponds much more closely to your "fwrite" call. Using the insertion operator ('<<') corresponds to using fprintf.
operator<<() and operator>>() operate on text-only files. That's why you get text. Instead, do something like this to mirror the other version:
fstream::write() and fstream::read() pretty much mirror fread() and fwrite() for FILE*s.
file.write((char*)&value, sizeof(value));fstream::write() and fstream::read() pretty much mirror fread() and fwrite() for FILE*s.
The binary flag for iostreams (and for FILE * for that matter) only refers to newline translations. Ex: if \n gets turned into \r\n. The iostream code you have uses operator<< for output which is the formatted output operator, this writes the number converted to a human readable string to the stream. It would be the same as if you used printf("%d",...) on the FILE *. Similarly your FILE * code would write the binary representation of value to the FILE * even if you opened the file in text mode.
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