the Question about Node and "if"

[NoobMathe]

void dfspostorder ( node ∗r ) {
if ( r ) {
dfspostorder ( r−>right ) ;
dfspostorder ( r−>left ) ;
cout << r−>i << endl ;
}

Hello,

I cant understand what this if (r) means here. If a pointer still points there, the recursion function will will move pointer to the right and left?

Thanks in advance

[Athar]

if (r) means "if r is not null".