Homework #7 – IntegerRange::iterator

IntegerRange.hh

#pragma once
#include <iterator>

// Represents all integer values in the range [low, high).
// low must be <= high.
template <typename Int>
struct IntegerRange
{
	struct iterator : public std::iterator<std::input_iterator_tag, Int>
	{
		iterator(const Int value) : value(value)
		{

		}

		iterator(const iterator& other) : value(other.value)
		{

		}

		bool operator!=(const iterator& other)
		{
			return value != other.value;
		}

		bool operator==(const iterator& other)
		{
			return value == other.value;
		}

		Int operator*(void)
		{
			return value;
		}

		iterator& operator++(void)
		{
			++value;
			return *this;
		}

		iterator operator++(int)
		{
			iterator old(*this);
			operator++();
			return old;
		}

		private:
		Int value;
	};

	IntegerRange(Int low, Int high) : low_(low), high_(high)
	{
		assert(low <= high);
	}

	const iterator begin() const
	{
		return iterator(low_);
	}

	const iterator end() const
	{
		return iterator(high_);
	}

	private:
	const Int low_;
	const Int high_;
};

test.cpp

#include <cassert>
#include <algorithm>

#include <iostream>
using std::cout;

#include <iterator>
using std::ostream_iterator;

#include "IntegerRange.hh"

int main(void)
{
	// int and std::find
	{
		IntegerRange<int> range(-2, 3);

		assert(std::find(range.begin(), range.end(), -2) == range.begin());
		assert(std::find(range.begin(), range.end(),  3) == range.end());
	}

	// short and std::for_each
	{
		IntegerRange<short> range(-2, 3);

		std::for_each(range.begin(), range.end(), [](short value)
		{
			static short expected = -2;

			assert(value == expected++);
		});
	}

	// long and std::count
	{
		IntegerRange<long> range(-2, 3);

		assert(std::count(range.begin(), range.end(), -2) == 1);
		assert(std::count(range.begin(), range.end(),  3) == 0);
	}

	// unsigned and std::equal
	{
		IntegerRange<unsigned>     range(2, 9);
		IntegerRange<unsigned>      same(2, 9);
		IntegerRange<unsigned> different(1, 9);

		assert(std::equal(range.begin(), range.end(),      same.begin()) == true);
		assert(std::equal(range.begin(), range.end(), different.begin()) == false);
	}
}