Re: In map iterator is there a difference between (*iter).second and iter->second?

Joe Greer <>
Wed, 20 Aug 2008 13:45:24 +0000 (UTC)
<Xns9B0063408FAEAjgreerdoubletakecom@> (Pascal J. Bourguignon) wrote in

Yes, but given a different class, they may be different:

#include <iostream>

class A {
public: int x;

class P {
    A a1;
    A a2;

    A& operator*(){ return(a1); }
    A* operator->(){ return(&a2); }

using namespace std;

int main(void){
    P p;
    cout<<"p->x = "<<p->x<<" ; (*p).x = "<<(*p).x<<endl;

Sadly, this points out all the worst in operator overloading. operator
overloading is meant to allow user defined types to have the same semantics
as built-in types, not creative and unexpected usage such as this where the
reader of the code would be quite surprised to discover the difference. It
is much like defining operater + to add a1 + a1 wherease operator - adds a2
+ a2. Both legal, but definitely a bad idea from a maintenance POV. In
real life, code is maintened for years after the original author lost all
interest in it and it is best to code with those folks in mind.


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