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++ operator overloading
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The ++ pre-fix and post-fix operators are the same, the only difference is that with the postfix first the current command is exexcuted and then the ++ operator, with the prefix it''s the other way round. There shouldn''t be a difference with overloaded operators.
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GA
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GA
Sorry ga, there is a difference...
The prefix version:
aclassfunction operator++ ()
{
}
The post-fix version:
aclassfunction operator++(int)
{
}
The ''int'' is just a dummy argument, thats it. Very subtle but very important!
Cheers
Matt
Check out my project at: www.btinternet.com/~Matthew.Bennett
The prefix version:
aclassfunction operator++ ()
{
}
The post-fix version:
aclassfunction operator++(int)
{
}
The ''int'' is just a dummy argument, thats it. Very subtle but very important!
Cheers
Matt
Check out my project at: www.btinternet.com/~Matthew.Bennett
3dModelMan is correct: the postfix operator++ needs a dummy argument of int. The prefix operator++ doesn''t need it.
Make sure that you''re returing the correct value: the postfix operator++ should return the value before the increment, the prefix operator++ should return the value after the increment. Of course you''re allowed to use different semantics, but it''ll confuse the users of your code.
Erik
Make sure that you''re returing the correct value: the postfix operator++ should return the value before the increment, the prefix operator++ should return the value after the increment. Of course you''re allowed to use different semantics, but it''ll confuse the users of your code.
Erik
I''m sorry for my wrong answer. I never needed overloading the ++ operator so I really didn''t expect that there would be a difference to the usual ++ operator.
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GA
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GA
If you don''t overload both, the compiler just uses the overloaded one for both cases.
- null_pointer
Sabre Multimedia
class USDollar
{
public:
USDollar() : nDollars(0), dCents(0) {};
protected:
unsigned int nDollars;
double dCents;
public:
USDollar& operator++();
};
USDollar& USDollar::operator++()
{
dCents++;
if( dCents >= 100 )
{
dCents = 0;
nDollars++;
}
return( *this );
}
main()
{
USDollar MyWallet();
// both of these work fine (in simple expressions)
MyWallet++;
++MyWallet;
return 0; // is this necessary? been a while since console apps...
}
- null_pointer
Sabre Multimedia
people who said you need a dummy argument are correct.
e.g.
class poo
{
int x;
poo operator++();
poo operator++(int notused);
};
// then just define the member functions
I looked that up in TYC++ third edition
just before making up that crappy example
the compiler distinguishes between the
pre and post-fix operators by that argument,
and in any calling case, it is passed the value of
zero.
Take it easy,
-Mezz
e.g.
class poo
{
int x;
poo operator++();
poo operator++(int notused);
};
// then just define the member functions
I looked that up in TYC++ third edition
just before making up that crappy example
the compiler distinguishes between the
pre and post-fix operators by that argument,
and in any calling case, it is passed the value of
zero.
Take it easy,
-Mezz
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