end of an Exe file in C++ - c++

Question

I am writing a C++ program to read an exe file. I wrote it and I test it on a text file instead of exe file. it was true.
when I test it with an exe file I understand that my exe file have 0x00 value in it (not at its end). so my while loop stop before end of file because I used:
class A{
private:
ifstream myFile;
void Read(char *filename)
};
void A::Read(char *str)
{
myFile.open(str,ios::binary);
while (!myFile.eof())
{
InputFile.get(ch);
myString.push_back(ch);
}
}
what should I do? if I should use size of the file, how can i get it?

Answer 1

You must open the file stream with the std::ios::binary mode flag.

Answer 2

As James McNellis pointed out you need to open the file in binary mode: Try something like the following:
#include <iostream>
#include <fstream>
int main()
{
std::ifstream in("main.obj", std::ios_base::binary);
std::streamsize bytes_read = 0;
if (in.is_open())
{
while (!in.eof())
{
char buf[1024];
// Use unformatted read.
in.read(buf, 1024);
if (in.gcount() > 0)
{
// The first 'in.gcount()' chars in
// 'buf' were read.
bytes_read += in.gcount();
}
}
}
in.close();
std::cout << "bytes read=" << bytes_read << "\n";
return 0;
}
EDIT:
Example modified to use get():
#include <iostream>
#include <fstream>
int main()
{
std::ifstream in("main.obj", std::ios_base::binary);
std::streamsize bytes_read = 0;
if (in.is_open())
{
while (!in.eof())
{
in.get();
if (1 == in.gcount())
{
bytes_read++;
}
}
}
in.close();
std::cout << "bytes read=" << bytes_read << "\n";
return 0;
}
Tested and works correctly.

Answer 3

In addition to opening the file in binary mode, the current code has a subtle bug which will cause the last character in the file to be read twice. The problem is that the myFile.eof() call does not do what you think it does. It does not tell you when you're at the end of the file. It tells you that you have tried to read beyond the end of the file. The idiomatic way to write a read-until-eof loop in C++ is:
while (myFile.get(ch))
myString.push_back(ch);
get returns an istream reference which, in this context, is implicitly convertible to bool and is used to indicate that there is no more data to read.

Answer 4

Only a hunch here, but my suspicion is that you're actually reading the whole file correctly, but measuring it wrong.
File reading (with binary mode) won't stop on a 0-byte, but there are several string related methods that will.
For example, you can't measure the size of a binary "blob" using strlen(), you can't copy it using strcpy().
Without seeing the actual way you're storing and measuring the data, it's hard to see where things go wrong, but I strongly suspect that you're actually reading the whole file correctly if you're using binary mode.

Answer 5

I found my mistake, The program read all the bytes but I cout that bytes in a vector<char>, So it's obvious I saw just bytes before 0x00.