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To read a binary file in C++ use read method. It extracts a given number of bytes from the given stream and place them into the memory, pointed to by the first parameter. If any error is occurred during reading in the file, the stream is placed in an error state, all future read operation will be failed then.
To read from a binary file For large binary files, you can use the Read method of the FileStream object to read from the file only a specified amount at a time. You can then limit how much of the file is loaded into memory for each read operation.
To open a file in binary format, add 'b' to the mode parameter. Hence the "rb" mode opens the file in binary format for reading, while the "wb" mode opens the file in binary format for writing. Unlike text files, binary files are not human-readable. When opened using any text editor, the data is unrecognizable.
To write to a binary fileUse the WriteAllBytes method, supplying the file path and name and the bytes to be written. This example appends the data array CustomerData to the file named CollectedData. dat .
If you want to do this the C++ way, do it like this:
#include <fstream>
#include <iterator>
#include <algorithm>
int main()
{
std::ifstream input( "C:\\Final.gif", std::ios::binary );
std::ofstream output( "C:\\myfile.gif", std::ios::binary );
std::copy(
std::istreambuf_iterator<char>(input),
std::istreambuf_iterator<char>( ),
std::ostreambuf_iterator<char>(output));
}
If you need that data in a buffer to modify it or something, do this:
#include <fstream>
#include <iterator>
#include <vector>
int main()
{
std::ifstream input( "C:\\Final.gif", std::ios::binary );
// copies all data into buffer
std::vector<unsigned char> buffer(std::istreambuf_iterator<char>(input), {});
}
Here is a short example, the C++ way using rdbuf. I got this from the web. I can't find my original source on this:
#include <fstream>
#include <iostream>
int main ()
{
std::ifstream f1 ("C:\\me.txt",std::fstream::binary);
std::ofstream f2 ("C:\\me2.doc",std::fstream::trunc|std::fstream::binary);
f2<<f1.rdbuf();
return 0;
}
sizeof(buffer) == sizeof(char*)
Use length instead.
Also, better to use fopen with "wb"....
sizeof(buffer) is the size of a pointer on your last line NOT the actual size of the buffer. You need to use "length" that you already established instead
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