Date Validation

[newbiecp]

This program works fine, but I need help on adding proper date validation. The code that I have will only check for integers 0-9, allow dashes in mm,dd,yyyy format, and not allow any strings. I want my program to catch invalid dates and recognize leap years. Is there a way I can add to the date validation function that I have currently in my code? I am using a regular expression, so I am asking if there is any way I can add to it valid dates,and check for leap year? Here is my code:

// inventory.cpp : Defines the entry point for the console application.
//

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <regex>
using namespace std;

const int DESC_SIZE = 50;

struct Date{
	int Month;
	int Day;
	int Year;
};

struct Inventory
{
	char desc[DESC_SIZE];	
	int quantity;
	double whlCost,
		   rtlCost;
	Date date;
};

void menu(std::fstream&);
bool addRecord(std::fstream&);
bool displayRecord(std::fstream&);
bool changeRecord(std::fstream&);
Date dateValidation(string);
bool isLeapYear();

int main()
{
		
	cout << fixed << showpoint << setprecision(2);
	fstream file;
	ifstream ifile("Inventory.dat");		
	if (!ifile)
	{
		Date date;
		date.Day = 1;
		date.Month = 1;
		date.Year = 1970;
		Inventory rec = {"Default", 0, 0.0, 0.0, date};
		file.open ("Inventory.dat", fstream::out | fstream::binary);
		for (int count = 0; count < 10; count++)
		{			
			file.write((char*)&rec,sizeof(rec));
		}
		cout << endl << "Warning, did not find file, so we created one.";
		cout << endl;		
		file.close();
	}	
	
	// Create Menu and run program
	menu(file);	
	system("pause");
	return 0;
	
}

Date dateValidation(string data){
	Date date;
    match_results<string::const_iterator> m;
    regex re("([0-9]+)-([0-9]+)-([0-9]*)?");	
    if (regex_match(data, m, re)) {
        date.Day = stoi(m[1].str()),
		date.Month = stoi(m[2].str()),
		date.Year = stoi(m[3].str());       
	}
	else date.Year = 0000;
	return date;
}

bool isLeapYear()
{
	Date date;

	if(date.Day%4)
		return false;
	if(date.Day%100)
		return true;
	if(date.Day%400)
		return false;
		return true;
}
	
	
void menu(std::fstream& file)
{	
	int choice = 0;
	bool success;
	while(choice!= 4) {
		cout << "Auto Zone Inventory" << endl;
		cout << endl << "1. Add new records to the file" << endl;
		cout << "2. Display any record in the file" << endl;
		cout << "3. Change any record in the file" << endl;
		cout << "4. Quit the program" << endl;
		cout << endl;
		cout << "Please enter your choice (1-4): ";
		cin >> choice;

		while (choice < 1 || choice > 4)
		{
			cout << endl << "Invalid entry. Please enter a number (1-4)" << endl;
			cin >> choice;
		}
		cout << endl;
	
		switch(choice){
			case 1:
					success = addRecord(file);					
					break;					
			case 2:
					success = displayRecord(file);
					break;
			case 3:
					success = changeRecord(file);
					break;
			case 4:	
					success = true;
					cout << "Thank you for using this program. Auto Zone cares!" << endl;
					break;
			default : 
					cout << "Error " << choice << " is not a valid number";
					break;
		}				
		if (!success) cout << "File IO Error reading file!";
		else {
			system("Pause");
			system("cls");
		}
		
	}
}

bool addRecord(std::fstream& file)
{
	cout << "Please enter new record data" << endl;
	Inventory rec;
	string dateStr;
	file.open ("Inventory.dat", fstream::out | fstream::app | fstream::binary);

	cout << endl << "Item Description:" << endl;
	cin.ignore();
	cin.getline(rec.desc, DESC_SIZE);
	cout << rec.desc << endl;
	cout << endl << "Quantity on hand:" << endl;
	cin >> rec.quantity;

	while (rec.quantity < 0)
	{
		cout <<  endl << "Invalid entry. Please enter only positive values." << endl;
		cin >> rec.quantity;
	}

	cout << endl << "Wholesale Cost" << endl;
	cin >> rec.whlCost;

	while (rec.whlCost < 0)
	{
		cout << endl << "Invalid entry. Please enter only positive values." << endl;
		cin >> rec.whlCost;
	}

	cout << endl << "Retail Cost" << endl;
	cin >> rec.rtlCost;

	while (rec.rtlCost < 0)
	{
		cout << endl << "Invalid entry. Please enter only positive values." << endl;
		cin >> rec.rtlCost;
	}
		
	bool loop = true;
	while (loop){ 
		cout << endl << "Date added to inventory (MM-DD-YYYY)" << endl;
		cin.ignore();
		cin >> dateStr;	
		rec.date = dateValidation(dateStr);		
		if (rec.date.Year != 0000) {			
			loop = false;
		}
		else 
			cout << endl << "Error Date Format is (MM-DD-YYYY)" <<endl;
	}
	file.write(reinterpret_cast<char *>(&rec),sizeof(rec));
	cout << endl << "Record added to inventory" << endl;
	file.close();
	return true;
}

bool displayRecord(std::fstream& file)
{
	Inventory rec;
	file.open ("Inventory.dat", fstream::in | fstream::binary);
	long num;
	//Figure out How many records exist
	long a = file.tellg();
	file.seekg(0, fstream::end);
	long b = file.tellg();
	long sizeFile = b - a;
	int c = sizeof(rec);
	int numRecords = (sizeFile / c);

	if (numRecords > 0){
		cout << "Please enter the record you would like to view (1-"<< (numRecords) <<")" << endl;
		cin >> num;
		if ((num >= 0) && (num <= (numRecords))){
			num = num -1;
			file.seekg(num * sizeof(rec), fstream::beg);
			file.read(reinterpret_cast<char *>(&rec), sizeof(rec));
			if (!file.eof())
			{
				cout << endl << "Here is your current record:" << endl;
				cout << endl << "Item Description: ";
				cout << rec.desc << endl;
				cout << "Quantity on hand: ";
				cout << rec.quantity << endl;
				cout << "Wholesale cost: ";
				cout << rec.whlCost << endl;
				cout << "Retail cost: ";
				cout << rec.rtlCost << endl;
				cout << "Date added to inventory: ";
				cout << rec.date.Day << "-" << rec.date.Month << "-" << rec.date.Year << endl;						
			}
			file.close();
		}
		else {
			cout << "Record Outside of Database Range" << endl;
		}
	}
	else {
		cout << "No Records Found !" << endl;
		return false;
	}
	return true;
}

bool changeRecord(std::fstream& file)
{
	Inventory rec;
	Inventory* recs;
	string dateStr;
	string yn;	
	char* buffer;	

	long num;
	
	file.open ("Inventory.dat", fstream::in | fstream::out | fstream::binary);
	
	//Figure out How many records exist
	long a = file.tellg();
	file.seekg(0, fstream::end);
	long b = file.tellg();
	long sizeFile = b - a;
	int numRecords = 0;
	if (sizeFile > 4){
		int c = sizeof(rec);
		numRecords = (sizeFile / c);
	}

	if (numRecords > 0){
		cout << "Please enter the record you would like to view (1-"<< (numRecords) <<")" << endl;
		cin >> num;
		if (!file.eof()){
			num = num -1;
			file.seekg(num * sizeof(rec), fstream::beg);
			file.read(reinterpret_cast<char *>(&rec), sizeof(rec));

			cout << endl << "Here is your current record" << endl;
			cout << endl << "Item description: ";
			cout << rec.desc << endl;
			cout << "Quantity on hand: ";
			cout << rec.quantity << endl;
			cout << "Wholesale cost: ";
			cout << rec.whlCost << endl;
			cout << "Retail cost: ";
			cout << rec.rtlCost << endl;
			cout << "Date added to inventory: ";
			cout << rec.date.Day << "-" << rec.date.Month << "-" << rec.date.Year << endl;
				
		}
		
		cout << endl << "Do you want to proceed ? (Y/N)" << endl;
		cin >> yn;
		if ((yn == "Y")||(yn == "y")){
			cout << endl << "Please enter your new data to the record"<< endl;
			cout << endl << "Item description:" << endl;
			cin.ignore();
			cin.getline(rec.desc, DESC_SIZE);
			cout << endl << "Quantity on hand:" << endl;
			cin >> rec.quantity;

			while (rec.quantity < 0)
			{
				cout << endl << "Invalid entry. Please enter only positive values." << endl;
				cin >> rec.quantity;
			}

			cout << endl << "Wholesale cost:" << endl;
			cin >> rec.whlCost;

			while (rec.whlCost < 0)
			{
				cout << endl << "Invalid entry. Please enter only positive values." << endl;
				cin >> rec.whlCost;
			}

			cout << endl << "Retail cost:" << endl;
			cin >> rec.rtlCost;

			while (rec.rtlCost < 0)
			{
				cout << endl << "Invalid entry. Please enter only positve values." << endl;
				cin >> rec.rtlCost;
			}

			bool loop = true;
			while (loop){ 
				cout << endl << "Date added to inventory (MM-DD-YYYY)" << endl;
				cin.ignore();
				cin >> dateStr;	
				rec.date = dateValidation(dateStr);		
				if (rec.date.Year != 0000) {			
					loop = false;
				}
				else 
					cout << endl << "Error Date Format is (MM-DD-YYYY)" <<endl;
			}

			file.seekp(num * sizeof(rec), fstream::beg);
			file.write(reinterpret_cast<char *>(&rec), sizeof(rec));
			cout << endl << "The Record has been edited." << endl;
		}
	}
	else cout << endl << "File contains no records!" << endl;
	file.close();
	return true;
}

[SamuelAdams]

A few strips of code you might like:

	const int daysInMonth [] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
	const int daysInMonthLeap [] = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

bool isALeapYear( int year )
{
	/* Check if the year is divisible by 4 or divisible by 400 */
	return ((year % 4 == 0 && year % 100 != 0) || ( year % 400 == 0));
}

	cin >> month >> day >> year;
	if ( month <= 0 || month > 12 || day <= 0 || day > 31 || year < 2000 || year > 2099 )
		{// code}