Hashtag symbol in C++ macro expression [duplicate]

Question

In the macro definition below, what does '#' symbol do? What is this syntax (#x) here?

#define print(x) cout<<(#x)<<" : "<<x<<endl;

Answer 1

# is the stringify operator. It turns the macro argument x into a string literal.

I can see no reason for the extra parens, #define print(x) cout << #x <<" : " << x << endl; would work just as well. Even better would be #define print(x) cout << #x <<" : " << (x) << endl; because the second use of x might require parens to be parsed correctly.