// This file compiles as a single unit, you can test it by saving it 
// as range_for.cpp and compiling with 
// g++ -std=c++11 -o range_for range_for.cpp
// Adjust the interface as you see fit
 
// Implementation (put this in a header)
// ------------------------------------------------------------------
 
 
/// encapsulates a range of integral numbers for use in a c++11 range-based for 
/// loop
template< typename T>
struct Range
{
    /// the begin() and end() functions must return an iterator with a specific
    /// interface
    struct Iterator
    {
        T val;  ///< storage for the actual value
 
        /// implicit construction from the value type
        Iterator( T val ):val(val){}
 
        /// the range-based for loops attempt to dereference an iterator using
        /// this operator
        T operator*(){ return val; }
 
        /// the range-based for loops quit when the comparison of iter != end
        /// returns false
        bool operator !=( T other ){ return val != other; }
 
        /// iterators in a range-based for loop must have the prefix increment
        /// operator
        Iterator& operator++(){ ++val; return *this; }
 
        /// we likely want to implicitly convert to the value type
        operator T(){ return val; }
    };
 
    private:
        T m_begin;  ///< the first integral value
        T m_end;    ///< one past the last integral value
 
    public:
        /// construct a range [begin, end)
        Range( T begin, T end ):
            m_begin(begin),
            m_end(end)
        {}
 
        /// interface required by range-based for loop
        Iterator begin(){ return m_begin; }
 
        /// interface required by range-based for loop
        Iterator end()  { return m_end;   }
};
 
 
/// return an object which can be used in a range-based for loop
template <typename T>
Range<T> range( T begin, T end )
{
    return Range<T>(begin,end);
}
 
 
 
 
// Usage 
// -------------------------------------------------------------------
 
#include <iostream>
 
int main(int argc, char** argv)
{
    std::cout << "Static ranges\n----------------\n";
    std::cout << "\nint:\n";
    for( int i : range(1,5) )
        std::cout << "   i: " << i << "\n";
 
    std::cout << "\nunsigned int:\n";
    for( unsigned int i : range(1u,5u) )
        std::cout << "   i: " << i << "\n";
 
    std::cout << "\nlong:\n";
    for( long i : range(1L,5L) )
        std::cout << "   i: " << i << "\n";
 
    std::cout << "\nDynamic range (program args)\n----------------\n";
    for( int i : range(0,argc) )
        std::cout << i << " : " << argv[i] << "\n";
 
    return 0;
}