Difference between string.empty and string[0] == '\0'

Question

Suppose we have a string

std::string str; // some value is assigned

What is the difference between str.empty() and str[0] =

Answer 1

Also, beware of the functions you'll use if you use C++ 11 or later version:

#include 
#include 

int main() {
    std::string str("\0ab", 3);

    std::cout << "The size of str is " << str.size() << " bytes.\n";
    std::cout << "The size of str is " << str.length() << " long.\n";
    std::cout << "The size of str is " << std::strlen(str.c_str()) << " long.\n";

    return 0;
}

will return

The size of str is 3 bytes.

The size of str is 3 long.

The size of str is 0 long.