Hi.
The following surprised me a lot: I thought that a subtraction of
a 'signed' and 'unsigned' integers has the type "signed",
but it seems the opposite:
-------------------------------------------------------
// u.cc
#include<iostream>
int main(){
int i(0); unsigned u(1);
bool isPos( i-u > 0 ); int res(i-u);
std::cout << i-u << ' ' << isPos << ' ' << res <<'\n';
}
g++ -ansi -pedantic -Wall u.cc
./a.out
4294967295 1 -1 <----------------- See the first two results
----------------------------------------------------------
1) Is type of 'signed-unsigned' defined in c++, or it is up to compiler ?
(is the above behaviour a failure ?)
2) Is there some way to convert a type of an expression into
_readable_ string ("typeof"), to debug such things ?
2b) Is it true that any legal expression has a type, or type
of some expressions may depend on context (i.e. type of
the lvalue they are assigned to, I know at least one case -
with function pointers, but is there more simple examples) ?
Thank you, regards
Dima.
