Question

I’m looking few exercise from university about C++ and I found out this exercise:

#include <iostream>
using namespace std;
int& f(int*&);
int& f(int*& x) {
    *x = 5;
    return *x;
}
int main() { 
    int y = 1, x; 
    int* z = &y; 
    x= f(z);
    cout << y << " " << x <<endl; 
}

I was wondering: does <any type>*& has any real sense? Isn’t f(int*& x) the same as f(int x)? Aren’t you passing the pointer to the L-value of the variable?

Answer 1

With int* &x you are passing the same pointer(by reference). Otherwise with only int* x you are passing a copy of the pointer and then you can’t change the original one in the function. &x makes x an alias of the original parameter.