Date Class - Invalid Inputs

[dsteemke]

I need to create a member function that checks for invalid date inputs as well as leap years. Any help would be greatly appreciated.

  #include <iostream>
#include <string>
#include <iomanip>
#include<limits>
using namespace std;

class Date
{
public:
	int m, d, y;
	void getDate();
	void checkDate();
	void displayDate1();
	void displayDate2();
	void displayDate3();
	void displayDate4();

	

private:
	void setMonths();
	int day;
	int month;
	int year;
	
};
string monthName[12] = { "January", "Febuary", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" };

int main()
{
	Date newdate;
	newdate.getDate (); 
	newdate.checkDate();
	newdate.displayDate1();
	newdate.displayDate2();
	newdate.displayDate3();
	newdate.displayDate4();
	system("pause");
	return 0;
}

void Date::getDate()
{
	cout << "The program displays a valid date in three different formats.\n";
	cout << "Note: All junk data will be rejected!\n";
	cout << "Enter a date(mm / dd / yyyy) or - 1 to end :";
	cin >> m;
	cin.get();
	cin >> d;
	cin.get();
	cin >> y;
	
}
void Date::checkDate()
{
	
}

void Date::displayDate1()
{
	cout << m <<"/"<< d<<"/" << y<<" (U.S.)"<<endl;

}

void Date::displayDate2()
{
	cout << monthName[m - 1] << " " << d << "," << y <<" (U.S. Expanded)"<< endl;
}
void Date::displayDate3()
{
	cout << d << " " << monthName[m - 1] << " " << y << " (U.S. Military)" << endl;
}
void Date::displayDate4()
{
	cout << y << "-" << m << "-" << d << " (International)" << endl;
}

[gunnerfunner]

the input validation checks needed for dates would be:
1. date b/w 1 and 31
2. if above condition satisfied then check, if data == 31, whether or not it's a short month i.e Apr, Jun, Sep, Nov
3. if month == Feb then check whether or not it's a leap year

the createDate() function below returns a Date object by value, so I've used a default Date object as the fall-back return value in case the input is not valid:

#include<iostream>
#include <algorithm>
#include <string>

const int monthUnder = 1;
const int monthOver = 31;

const std::vector<std::string> shortMonths{"Apr", "Jun", "Sep", "Nov"};
bool isShortMonth(const std::string& month)
{
   return (std::find(std::begin(shortMonths), std::end(shortMonths), month) != std::end(shortMonths)) ? true : false;
}
bool isLeapYear (const int& year)
{
    if(year % 4 != 0){	//not divisible by 4 - not leap year
		return false;
	}
	else
    {
        if((year % 100 != 0) && (year % 400 != 0))//divisible by 4, not divisible by 100
		return true;				//and not divisible by 400 - leap year

        if((year % 100 == 0) && (year % 400 !=0))//divisible by 4, divisible by 100
		return false; //and not divisible by 400 - not leap year

        if((year % 100 == 0) && (year % 400 == 0))//divisible by 4, divisible by 100
		return true;							//and divisible by 400 - leap year

		else return false;
	}
}
struct Date
{
    int m_day;
    std::string m_month;
    int m_year;
    Date(const int& day, const std::string& month, const int& year)
    : m_day(day), m_month(month), m_year(year){}
};
std::ostream& operator << (std::ostream& os, const Date& d)
{
    os << d.m_day << "/" << d.m_month << "/" << d.m_year;
    return os;
}

Date defaultDate = Date(1, "Jan", 2000);

Date createDate()
{
    int day{};
    do
    {
        std::cout << "Enter day \n";
        std::cin >> day;
    } while ((day < monthUnder) || (day > monthOver));
    std::cin.ignore();

    std::cout << "Enter month \n";
    std::string month{};
    getline(std::cin, month);

    std::cout << "Enter year \n";
    int year{};
    std::cin >> year;
    std::cin.ignore();

    if((day == monthOver) && isShortMonth(month))
    {
        std::cout << "31 selected as date for short month, returning default Date object \n";
        return defaultDate;
    }

    if(month == "Feb")
    {
        if((!isLeapYear(year)) && ( day > 28))
        {
            std::cout << "Non-leap year Feb cannot have more than 28 days, return default Date object \n";
            return defaultDate;
        }
        if((isLeapYear(year) && (day > 29)))
        {
            std::cout << "Leap year Feb cannot have more than 29 days, return default Date object \n";
            return defaultDate;
        }
        return Date(day, month, year);
    }
    return Date(day, month, year);
}

int main()
{
    std::cout << createDate();
}

[gunnerfunner]

OP: upon some further thought ... entering input in the order year -> month -> date ensures only valid Date objects are created by having a do/while loop at each stage that repeats until acceptable data are entered. this assumes that there is a pre-defined range for the year variable but if not, then data entry for year could be unrestricted. doing it in this order avoids the need for using any defaultDate object