#include <algorithm>
#include <functional>
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <vector>
using namespace std;
class RandomGenObj {
public:
RandomGenObj() {
srand(static_cast<int>(time(0)));
}
int operator()(int remainder) const {
return rand() % remainder;
}
};
int main() {
vector<int> v1(10, 10);
RandomGenObj rg();
random_shuffle(v1.begin(), v1.end(), rg);
for (vector<int>::const_iterator iter = v1.begin(); iter !=
v1.end(); ++iter)
cout << *iter << ' ' << endl;
cout << endl;
}
Above is the test program, I compiled it under gcc version 4.0.0
20050519(Red Hat 4.0.0-8), and the compiler output as follow:
/usr/lib/gcc/i386-redhat-linux/4.0.0/../../../../include/c
++/4.0.0/bits/stl_algo.h: In function ‘void
std::random_shuffle(_RandomAccessIterator, _RandomAccessIterator,
_RandomNumberGenerator&) [with _RandomAccessIterator =
__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int>
> >, _RandomNumberGenerator = RandomGenObj ()()]’:
random_shuffle.cpp:23: instantiated from here
/usr/lib/gcc/i386-redhat-linux/4.0.0/../../../../include/c
++/4.0.0/bits/stl_algo.h:1793: error: too many arguments to function
/usr/lib/gcc/i386-redhat-linux/4.0.0/../../../../include/c
++/4.0.0/bits/stl_algo.h:1793: error: no match for ‘operator+’ in
‘__first + (+ __rand)()’
/usr/lib/gcc/i386-redhat-linux/4.0.0/../../../../include/c
++/4.0.0/bits/stl_iterator.h:653: note: candidates are:
__gnu_cxx::__normal_iterator<_Iterator, _Container>
__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator+(const
typename std::iterator_traits<_Iterator>::difference_type&) const [with
_Iterator = int*, _Container = std::vector<int, std::allocator<int> >]
/usr/lib/gcc/i386-redhat-linux/4.0.0/../../../../include/c
++/4.0.0/bits/stl_bvector.h:267: note:
std::_Bit_iterator std::operator+(ptrdiff_t, const std::_Bit_iterator&)
/usr/lib/gcc/i386-redhat-linux/4.0.0/../../../../include/c
++/4.0.0/bits/stl_bvector.h:353: note:
std::_Bit_const_iterator std::operator+(ptrdiff_t, const
std::_Bit_const_iterator&)
however, if I rewrite the second line in function main as follow:
RandomGenObj rg;
Then the compiler pass the program, everything is right.
due to my limit knowledge in C++, I can't assure if it's due to
compiler's own problem.
I think in syntax there's no difference between "RandomGenObj rg;" and
"RandomGenObj rg()", since it has a default constructor.
I want to know if this is a compiler's error, and because I don't use
the lastest gcc compiler version, I want to know if in latest version
the problem has gone away.
