Can someone explain the output of this code [duplicate]

why is the output of this code "18 7 7". Is it because of my compiler.

#include <iostream>
using namespace std;

int main(){
    int x = 2 , y = 3 , z = 1;
    cout<<++x + ++x + x++<< x++ + ++y<<++z + z++ + x++;
    return 0;
}