how C++ Implicitly convert c style string to a string object?

Question

string s = "abc";

The above statement will first invoke string ( const char * s ) constructor, then invoke copy constructor according to What are the differences in string initialization in C++? . Here is the question: how C++ know it should invoke string ( const char * s ) to convert literal string "abc" to a temporary string object?

Note : copy constructor won't be invoked in copy initialization.

Answer 1

Initializing an object by using the syntax

string s = "abc";

is called copy initialization .

There are several scenarios where that is legal initialization. In all cases the RHS must be convertible to a string for it to work.

One way a string literal can be converted to a string is through the constructor of string that takes a char const* . That is called a user defined conversion .

Answer 2

Summary of all answers:

Reference:

1. http://en.cppreference.com/w/cpp/language/implicit_cast
2. http://en.cppreference.com/w/cpp/language/copy_initialization
3. http://en.cppreference.com/w/cpp/language/converting_constructor