C++ BinaryReader and BinaryWriter
I need to write an array of int to an output file as binary and also read the binary data as int in the programme in C++ Linux, something like the Bina开发者_运维百科ryReader and BinaryWriter in C#. How could I do that?
Thanks
Barring some outstanding reason to do otherwise, you'd typically use std::ostream::write
and std::istream::read
. Since you're producing a binary stream, you'll also typically want to specify std::ios::binary
when you open the file.
Just to flesh out Jerry and J-16 SDiZ's suggestions:
std::ofstream file(filename, ios::binary);
myFile.write (static_cast<const char*>(&x), sizeof x);
...
file.read(static_cast<char *>(x), sizeof x);
Further, you may want to consider putting the data in network byte-order if you need more portability: see the man-page (or equivalent) for ntohl et al on your system.
cast the array of int
to (char*)
and use istream::read
/ ostream::write
?
here is some code you might find useful:
bool readBinVector(const std::string &fname, std::vector<double> &val) {
long N;
std::fstream in(fname.c_str(), std::ios_base::binary | std::ios_base::in | std::ios::ate);
if(!in.is_open()) {
std::cout << "Error opening the file\n" << fname << "\n" << std::endl;
return false;
}
N = in.tellg()/(8);
val.resize(N);
in.seekg(0,std::ios::beg); // begeinning of file
in.read((char*)&val[0], N*sizeof(double));
in.close();
return true;
}
bool writeBinVector(const std::string &fname, const std::vector<double> &val) {
std::ofstream outfile (fname.c_str(),std::ofstream::binary);
outfile.write((char*)&val[0],val.size()*8);
outfile.close();
return true;
}
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