Observe:
class MyClass
{
public :
MyClass ( int x ) : i ( x ) {}
bool operator == ( const MyClass & other )
{ return i == other . i ; }
private :
int i ;
} ;
int main ( void )
{
MyClass a ( 1 ), b ( 2 ) ;
if ( a != b ) {}
}
Trying to compile this gives:
operator-notequal.cpp:14: error: no match for ‘operator!=’ in ‘a != b’
Now there need conceivably be no definition for operator != other than
the not-ted value of what operator == gives, so why does gcc want me to
define operator != separately?
Similarly even if I define only operator !=, gcc will tell me to
separately define operator == if I want to use that.
For the pairs:
== and !=
> and <=
< and >=
it is mathematically illogical to have any definition for each operator
in the pair which does not output same as the not-ted output of the
other operator in the pair, but gcc will not allow me to use an operator
unless it has been explicitly defined even if its logical negative
operator has been defined. I believe this is a defect in gcc.
Your comments?
Shriramana Sharma.
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