int main( )
{
        const double pi = 3.1415926535;
        // pi = 2.0; error: pi is read-only
        const double *p = π
        double t;
        p = &t;
        // *p = 10.0; error: read-only location

        const double *const cp = π
        // cp = &t; error, cp is read-only
}