//
// This is example code from Chapter 17.4.5 "The null pointer" of
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

//------------------------------------------------------------------------------

int main()
{
    double* p0 = 0;    // the null pointer

    if (p0 != 0) 
    {
        // consider p0 valid
    }

    if (p0)
    {
        // consider p0 valid; equivalent to p0!=0
    }
}

//------------------------------------------------------------------------------