How do I store a variable length string in C/C++

Question

Possible Duplicate:
What is the best way to slurp a file into a std::string in c++?

Im trying to store a whole text file as a string, how can I dynamically store any amount of characters the text file may contain?

Answer 1

The C++ Standard Library provides the std::string type for dynamically sized strings. It is a typedef for std::basic_string<char>. There's a useful reference at cppreference.com.

For reading lines from a file into a std::string, take a look at std::getline. You can use it to get a line from a file as follows:

std::string str;
std::getline(file_stream, str);

Be sure to check the stream (it is returned by std::getline) to see if everything went okay. This is often done in a loop:

while (std::getline(file_stream, str)) {
  // Use str
}

Answer 2

In addition to sftrabbit's answer:

Note that you can read a whole file into a string in one go by doing this:

std::ifstream input_ifstr(filename.c_str());

std::string str(
    (std::istreambuf_iterator<char>(input_ifstr)),
    std::istreambuf_iterator<char>());

input_ifstr.close();

You can construct a stringstream from it to process with getline afterwards if you wish.