employee.cpp

斯坦福Energy211/CME211课《c++编程——地球科学科学家和工程师》的课件

// Implementation file for the Employee class

#include "employee.h"

#include <stdexcept>

using namespace std;

Employee::Employee() {
	m_Name = "";
	m_SSN = "";
}

Employee::Employee( const string& name, const string& ssn ) {
	// Store arguments in member variables
	cout << "Constructing an employee!" << endl;
	m_Name = name;
	m_SSN = ssn;
	// Instead of throwing exception(), throw object
	// that can store an error message
	if ( IsValidSSN() == false )
		throw runtime_error( "Invalid SSN!" );
}

Employee::Employee( const Employee& e ) {
	// Copy data members from e
	m_Name = e.m_Name;
	m_SSN = e.m_SSN;
}

Employee::~Employee() {
	// Nothing to destroy here, because the data members
	// will be de-allocated automatically
	cout << "Destroying an employee!" << endl;
}

void Employee::SendTo( ostream& out ) const {
	// Output data members
	out << "Name: " << m_Name << endl;
	out << "SSN: " << m_SSN << endl;
	out << "Yearly Pay: $" << GetYearlyPay() << endl;
}

void Employee::GetFrom( istream& in, bool prompt ) {
	// Read data members
	if ( prompt == true )
		cout << "Enter First Name: ";
	string firstname;
	in >> firstname;
	if ( in == false )
		return;
	
	if ( prompt == true )
		cout << "Enter Last Name: ";
	string lastname;
	in >> lastname;
	
	// Use an output string stream to "write" the
	// first and last name to m_Name
	ostringstream os;
	os << firstname << " " << lastname;
	m_Name = os.str();
	
	if ( prompt == true )
		cout << "Enter SSN: ";
	in >> m_SSN;
	// Make sure SSN has valid format
	// Instead of throwing exception(), throw object
	// that can store an error message
	if ( IsValidSSN() == false )
		throw runtime_error( "Invalid SSN!" );
}

bool Employee::IsValidSSN() const {
	// Check SSN format by attempting to "read" a 3-digit
	// number, a dash, a 2-digit number, another dash, and
	// a 4-digit number from m_SSN
	istringstream is( m_SSN );

	// Read first number
	if ( GetSSNPart( is, 999 ) == false )
		return false;

	// Check for first dash
	char c = is.get();
	if ( is == false )
		return false;
	if ( c != '-' )
		return false;

	// Read second number
	if ( GetSSNPart( is, 99 ) == false )
		return false;
	
	// Check for second dash
	c = is.get();
	if ( is == false )
		return false;
	if ( c != '-' )
		return false;
	
	// Read third number
	if ( GetSSNPart( is, 9999 ) == false )
		return false;
	
	// Since we made it this far, it's valid!
	return true;
}

bool Employee::GetSSNPart( istringstream& is, int maxval )
{
	// Read an integer from a string and make sure it's
	// non-negative and does not exceed maxval.  We don't
	// care what its value is, so we don't return it
	int part(-1);
	is >> part;
	if ( is == false )
		return false;
	if ( part < 0 || part > maxval )
		return false;
	return true;
}

Employee& Employee::operator=( const Employee& e ) {
	// We don't need this operator to do anything since
	// we never want it to be used
	return *this;
}

ostream& operator<<( ostream& out, const Employee& e ) {
	// Regardless of the kind of employee is passed, the
	// appropriate SendTo function will be called, because
	// it's declared virutal in the Employee class
	e.SendTo( out );
	return out;
}

istream& operator>>( istream& in, Employee& e ) {
	// Only prompt if we're reading from cin, as opposed
	// to a file
	bool prompt = ( in == cin );
	// Regardless of the kind of employee is passed, the
	// appropriate GetFrom function will be called, because
	// it's declared virutal in the Employee class
	e.GetFrom( in, prompt );
	return in;
}