I need some help with std::regex_match because I'm trying to use in a Chapter 15 dril in PPP2

[DragonOsman]

The second part of the Drill in PPP2 Chapter 15, where you have to define the struct "Person". Namely, number 7 in the specifications:

Modify the constructor to check that age is [0:150) and that name doesn’t contain any of the characters ; : " ' [ ] * & ^ % $ # @ ! . Use error() in case of error. Test.

Note: The period in "bad characters" is not included in the characters themselves and is just a closing period.

Anyway, I'll show my code for the whole drill here, and as always, the drill specifications are included in the comments at the top.

// Chapter 15 Class definition drill
// Drill Specifications:
/**
* 1. Define a struct Person containing a string name and an int age.
* 2. Define a variable of type Person , initialize it with “Goofy” and 63, and
* write it to the screen ( cout ).
* 3. Define an input ( >> ) and an output ( << ) operator for Person ; read in a
* Person from the keyboard ( cin ) and write it out to the screen ( cout ).
* 4. Give Person a constructor initializing name and age .
* 5. Make the representation of Person private, and provide const member
* functions name() and age() to read the name and age.
* 6. Modify >> and << to work with the redefined Person .
* 7. Modify the constructor to check that age is [0:150) and that name doesn’t
* contain any of the characters ; : " ' [ ] * & ^ % $ # @ ! . Use error() in case
* of error. Test.
* 8. Read a sequence of Person s from input ( cin ) into a vector<Person> ;
* write them out again to the screen ( cout ). Test with correct and errone-
* ous input.
* 9. Change the representation of Person to have first_name and second_name
* instead of name . Make it an error not to supply both a first and a second
* name. Be sure to fix >> and << also. Test.
*/

#include "../../cust_std_lib_facilities.h"
#include <iostream>
#include <string>
#include <regex>

struct Person
{
	Person(const std::string &name, const int age);
	Person();
	std::string name() const { return m_name; }
	int age() const { return m_age; }
private:
	std::string m_name;
	int m_age;
};

std::ostream &operator<<(std::ostream &os, const Person &person);
std::istream &operator>>(std::istream &is, Person &person);

int main()
{
	using namespace std;

	try
	{
		Person p1{ "'[]*&^%$#@!", 150 };
	}
	catch (const runtime_error &rte)
	{
		cerr << "Runtime error: " << rte.what() << '\n';
	}

	keep_window_open();
}

Person::Person(const std::string &name, const int age)
	:m_name{ name }, m_age{ age }
{
	if (age < 0 || age > 150)
	{
		error("age out of range");
	}

	if (std::regex_match(m_name, std::regex("' [ ] * & ^ % $ # @ !")))
	{
		error("name contains invalid characters");
	}
}

Person::Person()
	: m_name{}, m_age{}
{
}

std::ostream &operator<<(std::ostream &os, const Person &person)
{
	return os << person.name() << " -- age: " << person.age();
}

std::istream &operator>>(std::istream &is, Person &person)
{
	using namespace std;

	string name;
	getline(is, name, '\n');
	int age;
	is >> age;

	person = Person::Person{ name, age };

	return is;
}

It won't the desired error message in case of the name containing bad characters. I think I'm using std::regex() wrong somehow, but how? Could someone help me?

I took out the code for specifications 2 and 3 where I had to add "Goofy" and read in a Person's name and age. I had them for a while, but I didn't think I need to keep them so I took them out.

[jlb]

If you want to use std::regex I suggest you study chapter 23 where std::regex is introduced, otherwise I suggest you think about using some of the std::string functions like find.first_of().

[DragonOsman]

Yeah, that sounds better. I'll use find() or find_first_of(), then. Thanks for the advice.

Edit: Now I need help with number 8, "Read a sequence of Persons from input (cin) into a vector<Person>; write them out again to the screen (cout). Test with correct and erroneous input."

Here's my code:

// Osman Zakir
// 6 / 23 / 2017
// Bjarne Stroustrup: Programming: Principles and Practice Using C++ 2nd Edition
// Chapter 15 Class definition drill
// Drill Specifications:
/**
* 1. Define a struct Person containing a string name and an int age.
* 2. Define a variable of type Person , initialize it with “Goofy” and 63, and
* write it to the screen ( cout ).
* 3. Define an input ( >> ) and an output ( << ) operator for Person ; read in a
* Person from the keyboard ( cin ) and write it out to the screen ( cout ).
* 4. Give Person a constructor initializing name and age .
* 5. Make the representation of Person private, and provide const member
* functions name() and age() to read the name and age.
* 6. Modify >> and << to work with the redefined Person .
* 7. Modify the constructor to check that age is [0:150) and that name doesn’t
* contain any of the characters ; : " ' [ ] * & ^ % $ # @ ! . Use error() in case
* of error. Test.
* 8. Read a sequence of Person s from input ( cin ) into a vector<Person> ;
* write them out again to the screen ( cout ). Test with correct and errone-
* ous input.
* 9. Change the representation of Person to have first_name and second_name
* instead of name . Make it an error not to supply both a first and a second
* name. Be sure to fix >> and << also. Test.
*/

#include "../../cust_std_lib_facilities.h"
#include <iostream>
#include <vector>
#include <string>

struct Person
{
	Person(const std::string &name, const int age);
	Person();
	std::string name() const { return m_name; }
	int age() const { return m_age; }
	void set_name(const std::string &name) { m_name = name; }
	void set_age(const int age) { m_age = age; }
private:
	std::string m_name;
	int m_age;
};

std::ostream &operator<<(std::ostream &os, const Person &person);
std::istream &operator>>(std::istream &is, Person &person);
void fill_person_v(std::vector<Person> &persons_v);
void print_person_v(const std::vector<Person> &persons_v);

int main()
{
	using namespace std;

	try
	{
		vector<Person> persons_v;
		fill_person_v(persons_v);
		print_person_v(persons_v);
	}
	catch (const runtime_error &rte)
	{
		cerr << "Runtime error: " << rte.what() << '\n';
	}
	catch (const out_of_range &oor)
	{
		cerr << "Out of range error: " << oor.what() << '\n';
	}

	keep_window_open();
}

Person::Person(const std::string &name, const int age)
	:m_name{ name }, m_age{ age }
{
	if (age < 0 || age > 150)
	{
		error("age out of range");
	}

	std::string bad_chars{ ":;''""[]*&^%$#@!" };
	for (std::size_t i = 0; i < m_name.size(); ++i)
	{
		if (m_name.find_first_of(bad_chars[i]))
		{
			error("name consists of invalid characters");
		}
	}
}

Person::Person()
	: m_name{}, m_age{}
{
}

std::ostream &operator<<(std::ostream &os, const Person &person)
{
	return os << person.name() << " -- age: " << person.age();
}

std::istream &operator>>(std::istream &is, Person &person)
{
	using namespace std;

	string name;
	getline(is, name, '\n');
	int age;
	is >> age;

	person = Person::Person{ name, age };

	return is;
}

void fill_person_v(std::vector<Person> &persons_v)
{
	using namespace std;
	cout << "Enter some people's name and age (separate name and age by 'Enter' keypress, please)\n"
		<< "end sequence of persons by entering '~'\n";
	for (Person person; cin >> person;)
	{
		char ch;
		cin.get(ch);
		if (ch != '~')
		{
			cin.putback(ch);
			persons_v.push_back(person);
		}
		else
		{
			cout << "Sequence ended\n";
			break;
		}
	}
}

void print_person_v(const std::vector<Person> &persons_v)
{
	using namespace std;
	for (std::size_t i = 0; i < persons_v.size(); ++i)
	{
		cout << persons_v.at(i) << '\n';
	}
}

I get the "invalid characters in name" error whatever name I enter. What am I doing wrong?