No output written to a.out

Hello,
I really need to know why my program is not working at all. The entire error message says:

Code:

Undefined                       first referenced
 symbol                             in file
Personal::Personal(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, long)/var/tmp//cchaaWiZ.o
ld: fatal: Symbol referencing errors. No output written to a.out
collect2: ld returned 1 exit status

Can anyone help me? Here is all of my code. I have been looking at it for hours trying to figure out what is wrong.

Code:

//Preprocessor Directives
#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

//Personal Class Declaration
class Personal 
	{
	private:
		string name;
		string address;
		int age;
		long phone;
		
	public:
		Personal();
		Personal(string, string, int, long);

		void setName(string);
		void setAddress(string);
		void setAge(int);
		void setPhone(long);
		string getName();
		string getAddress();
		int getAge();
		long getPhone();
	};

//Class Implementation
Personal::Personal()
{
	name = " ";
	address = " ";
	age = 0;
	phone = 0;
}
//Set name function definition
void Personal::setName(string pname)
{
	name = pname;
}
//Set address function definition
void Personal::setAddress(string paddress)
{
	address = paddress;
}
//Set age function definition
void Personal::setAge(int page)
{
	if(page < 0)
	{
		cout << "Invalid, age must be a positive integer." << endl;
	}
	else
		age = page;
}
//Set phone function definition
void Personal::setPhone(long pphone)
{
	phone = pphone;
}
//Get name function definition
string Personal::getName()
{
	return name;
}
//Get address function definition
string Personal::getAddress()
{
	return address;
}
//Get age function definition
int Personal::getAge()
{
	return age;
}
//Get phone function definition
long Personal::getPhone()
{
	return phone;
}

//Client Program
int main()
{
	//Temp Variables
	string personalname;
	string personaladdress;
	int personalage;
	long personalphone;
	
	//Instantiate three Personal objects
	Personal ashley("Ashley", "313 State St.", 21, 3209986);
	
	Personal alex("Alex", "705 4th St.", 24, 3402257);
	
	Personal input;
	
	//Gathering user input for Populating instance input
	cout << "Please enter your name: " << endl;
	cin >> personalname;
	cout << "Please enter your address: " << endl;
	cin >> personaladdress;
	cout << "Please enter your age: " << endl;
	cin >> personalage;
	cout << "Please enter your phone number: " << endl;
	cin >> personalphone;
	
	//Populates class instance input through set functions
	input.setName(personalname);
	input.setAddress(personaladdress);
	input.setAge(personalage);
	input.setPhone(personalphone);
	
	//Display the data members in the three instances of object Personal
	cout << left;
	cout << "Object ashley's contents" << endl;
	cout << "--------------------------" << endl;
	cout << setw(20) << "Name: " << ashley.getName() << endl;
	cout << setw(20) << "Address: " << ashley.getAddress() << endl;
	cout << setw(20) << "Age: " << ashley.getAge() << endl;
	cout << setw(20) << "Phone Number: " << ashley.getPhone() << endl;
	cout << "--------------------------------------------" << endl;
	
	cout << "Object alex's contents" << endl;
	cout << "--------------------------" << endl;
	cout << setw(20) << "Name: " << alex.getName() << endl;
	cout << setw(20) << "Address: " << alex.getAddress() << endl;
	cout << setw(20) << "Age: " << alex.getAge() << endl;
	cout << setw(20) << "Phone Number: " << alex.getPhone() << endl;
	cout << "--------------------------------------------" << endl;
	
	cout << "Object input's contents" << endl;
	cout << "--------------------------" << endl;
	cout << setw(20) << "Name: " << input.getName() << endl;
	cout << setw(20) << "Address: " << input.getAddress() << endl;
	cout << setw(20) << "Age: " << input.getAge() << endl;
	cout << setw(20) << "Phone Number: " << input.getPhone() << endl;
	cout << "--------------------------------------------" << endl;
	
	return 0; 
}

>> Personal::Personal(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, long)/var/tmp//cchaaWiZ.o

Learn how to read/interpret error messages. The function is declared but never defined.

>> Personal(string, string, int, long); // <- this needs a function body

Personal(string, string, int, long);

You have only declared, but not defined your second constructor.

Hi you guys,
Thanks a lot!!!! It was very useful. I had no idea that I had left such an important part out of my code. Thanks again!!!