how can i read binary data in c++? [closed] - c++

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I need to read and write binary data in C++.I use from ofstream and ifstream classes but it can't read some chars like 9,13,32.If is there another way to read and write theme.

Answer 1

Open the file using the std::ios::binary flag and then use .read(buffer,length); and .write(buffer,length); rather than the streaming operators.
There are some examples here:
https://cplusplus.com/reference/istream/istream/read/
https://cplusplus.com/reference/ostream/ostream/write/

Answer 2

Here is a program that does this:
#include <iostream>
#include <fstream>
int main(int argc, const char *argv[])
{
if (argc < 2) {
::std::cerr << "Usage: " << argv[0] << "<filename>\n";
return 1;
}
::std::ifstream in(argv[1], ::std::ios::binary);
while (in) {
char c;
in.get(c);
if (in) {
::std::cout << "Read a " << int(c) << "\n";
}
}
return 0;
}
Here is an example of it being run in Linux:
$ echo -ne '\x9\xd\x20\x9\xd\x20\n' >binfile
$ ./readbin binfile
Read a 9
Read a 13
Read a 32
Read a 9
Read a 13
Read a 32
Read a 10

Answer 3

This is a basic example (without any error check!):
// Required STL
#include <fstream>
using namespace std;
// Just a class example
class Data
{
int a;
double b;
};
// Create some variables as examples
Data x;
Data *y = new Data[10];
// Open the file in input/output
fstream myFile( "data.bin", ios::in | ios::out | ios::binary );
// Write at the beginning of the binary file
myFile.seekp(0);
myFile.write( (char*)&x, sizeof (Data) );
...
// Assume that we want read 10 Data since the beginning
// of the binary file:
myFile.seekg( 0 );
myFile.read( (char*)y, sizeof (Data) * 10 );
// Remember to close the file
myFile.close( );