range.cc

#include <iostream>

#define let(v, x) __typeof(x) v = (x)
#define foreach(i,v) for(let(i, (v).begin());i!=(v).end();++i)

using namespace std;

template<typename T> struct wrap_itr //{{{
: public iterator<bidirectional_iterator_tag, T>{
    typedef wrap_itr<T> It;
    T t;
    wrap_itr(T t): t(t){}
    It& operator++(){++t; return *this;}
    It& operator--(){--t; return *this;}
    T operator*(){return t;}
    friend bool operator!=(const It &x, const It &y){
        return x.t != y.t;
    }
    operator T(){return t;}
    It& operator()() {return *this;}
}; //}}}
struct range { //{{{
    typedef wrap_itr<int> iterator;
    typedef iterator It;
    It begin, end;
    range(int b, int e=0) : begin(min(b,e)), end(max(b,e)){}
    bool include(int x){return begin <= x && x < end;}
}; //}}}

int main(void){
    foreach(i, range(10)) cout << i << endl;
    return 0;
}