martin-minarik/main.cpp

## main.cpp
#include <iostream>
#include <stack>
#include <regex>

using namespace std;

void print_tags(string text);

bool is_start_tag(const string &element);

bool check_html_tags_parity(string text);

int main()
{
    cout << boolalpha;

    // Demonstration 1
    {
        const string html_test_string = "<body>\n"
                                        "    <h1> foobar </h1>\n"
                                        "</body>\n";
        print_tags(html_test_string);
        cout << check_html_tags_parity(html_test_string) << endl;
    }

    cout << endl;

    // Demonstration 2
    {
        const string html_test_string = "<body>\n"
                                        "    <h1> foobar </h1>\n";
        print_tags(html_test_string);
        cout << check_html_tags_parity(html_test_string) << endl;
    }

    return 0;
}

void print_tags(string text)
{
    smatch match;
    regex regex_("</?.+?>");

    while (regex_search(text, match, regex_))
    {
        cout << match[0].str() << " ";
        text = match.suffix();
    }
    cout << endl;
}

bool is_start_tag(const string &element)
{
    return element[1] != '/';
}

bool check_html_tags_parity(string text)
{
    stack<string> stack_;
    smatch match;
    regex regex_("</?(.+?)>");

    while (regex_search(text, match, regex_))
    {
        string element = match[0].str();
        string tag = match[1].str();
        if (is_start_tag(element))
            stack_.push(tag);
        else
        {
            if (!stack_.empty())
            {
                if (stack_.top() == tag)
                    stack_.pop();
                else
                    return false;
            }
            else
                return false;
        }

        text = match.suffix();
    }

    return stack_.empty();
}
	#include <iostream>
	#include <stack>
	#include <regex>

	using namespace std;

	void print_tags(string text);

	bool is_start_tag(const string &element);

	bool check_html_tags_parity(string text);

	int main()
	{
	cout << boolalpha;

	// Demonstration 1
	{
	const string html_test_string = "<body>\n"
	" <h1> foobar </h1>\n"
	"</body>\n";
	print_tags(html_test_string);
	cout << check_html_tags_parity(html_test_string) << endl;
	}

	cout << endl;

	// Demonstration 2
	{
	const string html_test_string = "<body>\n"
	" <h1> foobar </h1>\n";
	print_tags(html_test_string);
	cout << check_html_tags_parity(html_test_string) << endl;
	}

	return 0;
	}

	void print_tags(string text)
	{
	smatch match;
	regex regex_("</?.+?>");

	while (regex_search(text, match, regex_))
	{
	cout << match[0].str() << " ";
	text = match.suffix();
	}
	cout << endl;
	}

	bool is_start_tag(const string &element)
	{
	return element[1] != '/';
	}

	bool check_html_tags_parity(string text)
	{
	stack<string> stack_;
	smatch match;
	regex regex_("</?(.+?)>");

	while (regex_search(text, match, regex_))
	{
	string element = match[0].str();
	string tag = match[1].str();
	if (is_start_tag(element))
	stack_.push(tag);
	else
	{
	if (!stack_.empty())
	{
	if (stack_.top() == tag)
	stack_.pop();
	else
	return false;
	}
	else
	return false;
	}

	text = match.suffix();
	}

	return stack_.empty();
	}