How exactly does the below program works?

Question

#include<iostream>
using namespace std;
int main()
{
int i=1,2,3,4,5;
int j=(1,2,3,4,5);
cout<<i<<" "<<j<<endl;
}

The output of the above code is 1 5 . Why is the value of i 1 and j is 5 ? And how does the compiler evaluate the expression ?