Parnost i deljivost

Napisati funktore is_even is_odd, i is_divisible_by koji proveravaju da li je broj paran, neparan, odnosno deljiv sa zadatim brojem.

Test

#include <iostream>
#include <vector>

namespace matf {

	template <typename ForwardIt, typename UnaryPredicate>
	size_t count_if(ForwardIt first, ForwardIt last, UnaryPredicate p)
	{
		size_t count = 0;
		for (ForwardIt it = first; it != last; ++it) {
			if (p(*it)) {
				++count;
			}
		}
		return count;
	}
	
    // Ovde idu vase implementacije

} // namespace matf

int main(void)
{
	std::vector<int> vec = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

	size_t even_count = matf::count_if(vec.begin(), vec.end(), matf::is_even());
	std::cout << "Number of even elements: " << even_count << std::endl;

	size_t odd_count = matf::count_if(vec.begin(), vec.end(), matf::is_odd());
	std::cout << "Number of odd elements: " << odd_count << std::endl;

	size_t divisible_by_3_count = matf::count_if(
		vec.begin(), vec.end(),
		matf::is_divisible_by(3)
	);
	std::cout << "Number of elements divisible by 3: " << divisible_by_3_count << std::endl;

	return 0;
}

Rešenje

`main.cpp`

#include <iostream>
#include <vector>

namespace matf {

	template <typename ForwardIt, typename UnaryPredicate>
	size_t count_if(ForwardIt first, ForwardIt last, UnaryPredicate p)
	{
		size_t count = 0;
		for (ForwardIt it = first; it != last; ++it) {
			if (p(*it)) {
				++count;
			}
		}
		return count;
	}
	
	struct is_even {
		bool operator()(int value) const
		{
			return value % 2 == 0;
		}
	};

	struct is_odd {
		bool operator()(int value) const
		{
			return value % 2 != 0;
		}
	};

	struct is_divisible_by {
		int divisor;

		is_divisible_by(int _divisor) : divisor(_divisor) {}

		bool operator()(int value) const
		{
			return value % divisor == 0;
		}
	};

} // namespace matf

int main(void)
{
	std::vector<int> vec = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

	size_t even_count = matf::count_if(vec.begin(), vec.end(), matf::is_even());
	std::cout << "Number of even elements: " << even_count << std::endl;

	size_t odd_count = matf::count_if(vec.begin(), vec.end(), matf::is_odd());
	std::cout << "Number of odd elements: " << odd_count << std::endl;

	size_t divisible_by_3_count = matf::count_if(
		vec.begin(), vec.end(),
		matf::is_divisible_by(3)
	);
	std::cout << "Number of elements divisible by 3: " << divisible_by_3_count << std::endl;

	return 0;
}