Which of the following function is more appropriate for reading in a multi-word string?

The function that is more appropriate for reading in a multi-word string is getline() in C++. This function is used to read a string or a line from an input stream. It is more appropriate for reading multi-word strings because it can read spaces, which are typically used to separate words.

Here is how you can use it:

#include <iostream>
#include <string>

int main() {
    std::string str;

    std::cout << "Enter a multi-word string: ";
    std::getline(std::cin, str);

    std::cout << "You entered: " << str << std::endl;

    return 0;
}

In this code, std::getline(std::cin, str) reads a line from the standard input (which is usually the keyboard) and stores it in the string str. It stops reading when it encounters a newline character ('\n'), which is typically entered when you press Enter.