Assigning/Initializing references in function args

Question

I am from C background and trying to understand what this means:

void f(const string &x = "hello") {
}

Is x set to a default value if nothing is passed in? Where does "hello" reside?

Answer 1

Your parameter (x) is created/initialized in the context of the calling function. The string literal `"hello" has static storage duration.

The standard doesn't specify the form of memory in which either of those is stored, but in a typical case, the string literal will reside in some memory that's initialized directly from data in the executable file, and x will be created on the stack (with the address of the literal passed to initialize it if you don't pass something else in its place).