How can I make a new c++ style string with a character from a previous string?

Question

This is the piece of code I have. I am new, but enthusiastically learning c++. I am curious to why when I try to declare a new variable first_letter as a string, to hold the value of my previous string variable greetings first letter, this error code appears. No viable conversion from 'std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::value_type' (aka 'char') to 'std::string' (aka 'basic_string<char, char_traits<char>, allocator<char> >')

 int main()
    {
        std::string greetings = "hello";
        std::string first_letter = greetings[0];
        std::cout<<first_letter;
        return 0;
    }

I understand bit about char and how it holds characters as an integer and is interchangeable. Feel free to explain it as hard as you need, I will look up your detailed things on google as well to learn them. Thank you.

Answer 1

There is no implicit conversion from char to string. You can use the constructor

std::string first_letter(1, greetings[0]);

or

std::string first_letter(greetings, 0, 1);

Answer 2

There is no implicit constructor of std::string that takes a char . However, you can construct the string from a char like this:

std::string first_letter { greetings[0] };

Here's a demo .