What does a statement like "int& p = a" mean?

Question

This is the code from one test:
//------------------------------
#include <iostream>
using namespace std;

int main() {

int a = 5;
int& p = a;
p-=1;
//cout << a;
return 0;
}
//------------------------------

I can't understand what does the statement "int& p = a ;" do. It doesn't compile without the next one "p-=1;".
Would somebody explain it's sense to me?

My Eng. is not good, sorry.

Answer 1

That is a reference.

You are creating another variable name that you can use instead of a.

So you can use either a or p for the same effect.

Answer 2

Сергей Куликов there are ton of resources online to learn any language you want(including sololearn).
For best results I would suggest a culmination of them and sololearn

Answer 3

int& p= a;
binds the integer reference p to a. The address of the variable p is completely unmodified.
It simply means that all uses (references) of a actually use the value assigned to a.

Answer 4

Thanks to all for the help. I'm in a trip now and don't have my c++ book whith me. Did not find anything about that in Sololearn c++ course.