If one side of the expression is longer, putting the shorter one first can improve readability. (Some would argue that you should assign the longer expression t

If one side of the expression is longer, putting the shorter one first can improve readability. (Some would argue that you should assign the longer expression to a variable first). I think that if(S_OK == QueryInterface(IID_IUnknown, &p)) { is clearer than if(QueryInterface(IID_IUnknown, &p) == S_OK) {