C++ - Weird thing, input got reversed -

i found weird, tested code:

#include <iostream> using namespace std;  int main() {     int i=0, a[5];     cin>>a[i++]>>a[i++]>>a[i++];     for(int j=0; j<i; j++){         cout<<a[j]<<endl;     } } 

with input:

1 2 3 

and got input reversed this:

3 2 1 

i thought output should same code:

#include <iostream> using namespace std;  int main() {     int i=0, a[5];     cin>>a[i++]; cin>>a[i++]; cin>>a[i++];     for(int j=0; j<i; j++){         cout<<a[j]<<endl;     } } 

anybody had experienced before? thanks.

-edit-

thanks answers!!!

cin>>a[i++]>>a[i++]>>a[i++]; 

is syntactic sugar for

cin.operator>>(a[i++]).operator>>(a[i++]).operator>>(a[i++]); 

now, 3 calls operator>> executed left right, 3 arguments a[i++] can evaluated in order. let's call arguments x, y , z:

cin.operator>>(x).operator>>(y).operator>>(z); 

you might expect compiler substitute x, y , z follows:

int& x = a[i]; i++; int& y = a[i]; i++; int& z = a[i]; i++; 

but in fact, compiler give more freedom. in case, chose:

int& z = a[i]; i++; int& y = a[i]; i++; int& x = a[i]; i++; 

and james kanze points out, have chosen:

int& x = a[i]; int& y = a[i]; int& z = a[i]; i++; i++; i++;