same thing?

[modern oriole]

in first you printing second n from reference, in second you print second n like first n

it works the same

but i dont recommend creating a int& variable

because why

why you need to create it

you can just print n twice

and it will work

from reference you can change the n(if im not mistaken)

so

you just creating a reference object which does nothing

second variant is better i think

[modern oriole]

and

dont use global variables

give me a minute

i will try to explain

int main()
{
    int n = 234; /* this is local variable because it is in function */

} // n will be destroyed here
-----------------------------------------------------------------
if(int n = some_function();  n == 2) /* n is local variable because it was created in if statement*/
{
    n += 2;
}// n will be destroy here
-----------------------------------------------------------------
int n = 234; /* n is a global variable because it wasn't created in function, or if statements, switch statements etc. */
int main()
{
    if(int n = some_function();  n == 52)
    {
        n += 7;
    }
}

i'll recomend you to change printN function like that

#include <iostream>
void print_number_twice(int n)
{
    std::cout << n << '\n' << n << '\n';
}
int main(void)
{
    int n{2};
    print_number_twice(n);
}

and make this

#include <iostream>
void print_number_twice(int);
int main(void)
{
    int n{2};
    print_number_twice(n);
}
void print_number_twice(int n)
{
    std::cout << n << '\n' << n << '\n';
}

or put the function to the .h file like this

// functions.h
#ifndef FUNCTIONS_H
#define FUNCTIONS_H
void print_number_twice(int);
#endif

// functions.cpp
#include <iostream>
#include "functions.h"
void print_number_twice(int n)
{
    std::cout << n << '\n' << n << '\n';
}

// main.cpp
#include "functions.h"
int main(void)
{
    int n{2};
    print_number_twice(n);
}