why std::string is not implicitly converted to bool

Question

Is there a reason why in c++ std::string is not implicitly converted to bool? For example

std::string s = \"\"
if (s) { /* s in not empty */ }
         


        

Answer 1

This article mentions some reasons why operator bool() can lead to surprising results.

Note that std::string is just a typedef for std::basic_string. There is also std::wstring for multi-byte characters. An implicit conversion would let you write:

std::string foo = "foo";
std::wstring bar = "bar";
if (foo == bar) {
  std::cout << "This will be printed, because both are true!\n";
}