Pointers in C++

Using the Deferencing Operator

Since g is a pointer, we can't use, for example, g.pile1
to access a member. We have to dereference the pointer first.

However,

  *g.pile1

will not work because the member operator '.' has higher precedence than '*'.

  (*g).pile1

will work. Now,

void clear(gameState *g) { (*g).pile1 = 0; (*g).pile2 = 0; }

will succeed in modifying the original struct.