C++ Programming :: typeid question


	typeid question Hi All, I have the following: class ClassA { }; class ClassB { }; int main(){ ClassA a; ClassB b; cout << typeid(a).name() << endl; cout << typeid(b).name() << endl; } when this executes it prints: 6ClassA 6ClassB Where does the '6' come from? Thanks for your help Regards Michael michael a crit : > [snip] > cout << typeid(a).name() << endl; > cout << typeid(b).name() << endl; > when this executes it prints: > 6ClassA > 6ClassB > Where does the '6' come from? It is the length of the string I guess. Note: The output of typeid().name() is implementation defined. Michael On May 14, 12:31 pm, "michael" <s@begone.net> wrote: - Hide quoted text - > Hi All, > I have the following: > class ClassA { > }; > class ClassB { > }; > int main(){ > ClassA a; > ClassB b; > cout << typeid(a).name() << endl; > cout << typeid(b).name() << endl; > } > when this executes it prints: > 6ClassA > 6ClassB > Where does the '6' come from? > Thanks for your help > Regards Michael I compiled your code on my Solaris box and it gave me correct results. ./a.out classA classB I used Sun Studio11 C++ compiler. Cheers -Vallabha S7 Software Solutions http://www.s7solutions.com/ - Hide quoted text - Vallabha wrote: > On May 14, 12:31 pm, "michael" <s@begone.net> wrote: >> Hi All, >> I have the following: >> class ClassA { >> }; >> class ClassB { >> }; >> int main(){ >> ClassA a; >> ClassB b; >> cout << typeid(a).name() << endl; >> cout << typeid(b).name() << endl; >> } >> when this executes it prints: >> 6ClassA >> 6ClassB >> Where does the '6' come from? >> Thanks for your help >> Regards Michael > I compiled your code on my Solaris box and it gave me correct results. > ./a.out > classA > classB The results are correct on both machines. The return of typeid is implementation specific. There's no guarantee that it's meaningful to humans at all. It's certainly NOT unique (nor required to be) for distinct types. On May 14, 3:29 pm, Ron Natalie <r@spamcop.net> wrote: - Hide quoted text - > Vallabha wrote: > > On May 14, 12:31 pm, "michael" <s@begone.net> wrote: > >> I have the following: > >> class ClassA { > >> }; > >> class ClassB { > >> }; > >> int main(){ > >> ClassA a; > >> ClassB b; > >> cout << typeid(a).name() << endl; > >> cout << typeid(b).name() << endl; > >> } > >> when this executes it prints: > >> 6ClassA > >> 6ClassB > >> Where does the '6' come from? > >> Thanks for your help > > I compiled your code on my Solaris box and it gave me correct results. > > ./a.out > > classA > > classB > The results are correct on both machines. The return of typeid is > implementation specific. There's no guarantee that it's meaningful > to humans at all. It's certainly NOT unique (nor required to be) for > distinct types. In fact, an empty string for every type would also be conforming. It's also not required to be the same for the same type; outputting the address of the typeid object would also be conform. (On the other hand, it's implementation defined, so the implementation is required to document what it does.) Some implementations choose to do something useful. Others not. -- James Kanze (GABI Software) email:james.ka@gmail.com Conseils en informatique oriente objet/ Beratung in objektorientierter Datenverarbeitung 9 place Smard, 78210 St.-Cyr-l'cole, France, +33 (0)1 30 23 00 34