Pointers & const

#include <iostream>

using namespace std;

int main()
{
        int i1 = 5, i2 = 3;
        const int* pi1 = &i1;
        int* const pi2 = &i2;

        // the next line prints 5 3
        cout << *pi1 << ' ' << *pi2 << endl;

        // the next line is compile error - try to modify to const int
        // *pi1 = 7;

        pi1 = &i2;
        // the next line prints 3 3
        cout << *pi1 << ' ' << *pi2 << endl;

        // the next line is compile error - try to modify to const int pointer
        // pi2 = &i2;

        pi1 = &i1;
        *pi2 = 7;
        // the next line prints 5 7
        cout << *pi1 << ' ' << *pi2 << endl;

        return 0;
}