using classes for calendar helper

[ocKiNOsIi]

Really need help on this

L48 I am getting this error "'Day' is missing exception specification 'noexcept'"
what does it mean and how can I fix that?

I know this would work for printing out the day as January 1.. how do I correctly implement the day of the week?
If user chooses to display day 1 I want the output to be "Fri Jan 1, 2021".

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
// error message
template<typename T> // useful for getting user's keyboard input without crash or hang
T kbd_input(const string &prompt="Enter: ", const string &errmsg="  Oops! Try again.\n\n") {
  while (true) {
    cout << prompt; T ans{};
    if (cin>>ans) return ans;
    else {
      cin.clear(); cin.ignore(INT_MAX, '\n'); cout<<errmsg;
    }
  }
}
const int NUM_MONTHS = 13;

// class
class Day {
  private:
    int day_of_year; // To hold a day
    string month; // To hold a month name
    int arrayIdx; // Stores an array index
    
  public:
    // month:
    static const int daysInMonth[12];
    static const int daysInMonth_accum[12];
    static const string monthsOfYear[NUM_MONTHS];
    enum month_t {jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec};
    const static int daysInYear[NUM_MONTHS];
    // week
    static const string daysOfWeek[7];
    enum weekday_t {sun, mon, tue, wed, thr, fri, sat};
    // day
    static const int BASE_YEAR=2021;
    static const month_t BASE_MONTH=jan;
    static const weekday_t BASE_WEEKDAY=fri; // January 1, 2021 was a Friday
    static const int BASE_DAY=1;
    explicit Day( int ndays = 1 ) noexcept ; // constructor
    // implement 3 constructors, ++day, day++, --day, day--; "show", "print", "display", << as needed
    Day operator++(int);
    Day operator--(int);
    Day operator++();
    Day operator--();
    // Members can be here (inline) or after.
    
    Day(int d)
    {
        day_of_year = d;
    }

    void print();
};

// initialized monthsOfYear, daysOfWeek, daysInMonth, daysInMonth_accum
const string Day::monthsOfYear[] = {"january", "february",
    "march", "april", "may", "june", "july", "august", "september", "october", "november",
    "december"};
const string Day::daysOfWeek[7] = {"sunday", "monday", "tuesday", "wednesday", "thursday", "friday", "saturday"};
const int Day::daysInMonth[12] = {31, 28, 31, 30,  31,  30,  31,  31,  30,  31,  30,  31};
const int Day::daysInMonth_accum[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
// limits day to positive numbers after 1 / no error message
Day::Day( int ndays ) noexcept:day_of_year( std::min( 1, ndays ) ) {}


void Day::print()
{
    bool isFound = false;
    
    for (int count = 0; count < NUM_MONTHS && isFound != true; count++)
    {
        if (day_of_year <= daysInYear[count])
        {
            cout << monthsOfYear[count] << " " << (day_of_year %= daysInYear[count-1]);
            isFound = true;
        }
    }
}


int main() {
    int number = 0;
    cout <<"Welcome to ????'s calendar helper!\n";
    Day day; // this is updated in the set day options, and is the 1st day displayed in the Display options.
    for (bool running=true; running; ) {
    cout<<"\nOptions: Display d)ay w)eek m)onth; s)et-day t)esting q)uit: ";
    string option; char option_letter; cin>>option; option_letter=tolower(option[0]);
    switch (option_letter) {
      case 's': // set day, test constructors: Day(), Day(int) constructor
        {
          char option = tolower(kbd_input<char>("  set day d)efault m)month,day n)umber v)ary: "));
          if (option=='q') break;
          
          switch(option) {
            case 'd': {
                cout << "enter a day number (day#=[1]): ";
          //      getline(cin, monthName);
              //  day 1 = Jan 1 2021
              //  day 366 = jan 1, 2022
              break;
            }
            
            case 'm': {
                cout << "enter a month (3-letter-month, like: jan): ";

              break;
            }

            case 'n': {
                cout <<"enter a day of the year (1-365): ";
                // can only change number of day
                // this only changes the day within the year
                // cannot go into next year
              break;
            }
            case 'v': {
                /*
                cout <<"the current day is : "<< 500;
                cout<< "\n+/- number to vary current day: ";
                cin<< // if they enter -100 remove 100 days from current day.
                cout <<"\ncurrent day is now: ";
                cout <<"\nday#=["<<865<<"]"<< mon may 15, 2023;
                // subtracts day from current day. day can be over 365
                //cannot subtract 366 from 365 */
              break;
            }

            default:
              cout<<"Invalid option, try again. q to quit."; break;// continue;
          }
          // cout<<"  day#=["<<day<<"] "<<day.to_string()<<endl; // generic output. Could be helpful.
          break;
        } // case 's' for set day
            
      case 'd': {
          cout<<"You chose to display the current day...\n";

          cout << "Please enter a day (1 through 365): ";
          cin >> number;

          while (number <= 0 || number > 365)
          {
              cout << "Please enter a day (1 through 365): ";
              cin >> number;
          }

          // Create a DayOfYear class object
          Day day_of_year(number);
          day_of_year();

          break;
        }
        
      case 'm': {
          cout<<"You chose to display the current month...\n";
          
          break;
        }
        
      case 'w': {
          cout<<"You chose to display the current week...\n";
          break;
        }
        
      case 't': {
          cout<<"t option - test increment, decrement operators, TO BE IMPLMENTED\n";
          break;
        }
            
      case 'q':
        running=false;
        break;
        
      default:
        cout<<"  Invalid option, try again. q to quit.\n";
        break;
    }
  }
  cout<<"\nThanks for using ??????'s calendar helper!\nGood-bye!\n";
}

should I be working on case s and everything inside it first?
Case s allows the user to set any day in 2021,2022,and 2023.

Options: Display d)ay w)eek m)onth; s)et-day t)esting q)uit: s
set day d)efault m)month,day n)umber v)ary: n
number day of year (1-365...): 500
day#=[500] sun may 15, 2022

The rest just print the day, week, and month based on what the user set the "current day" as
I should be using my base days in this..

[AbstractionAnon]

Line 48 and line 68 must match. L64 has noexcept, line 48 does not.
See next item also.

Line 40: You're declaring your desstructor constructor. Line 48: You're trying to implement your destructor constructor inside your class. You can do one or the other. You can not do both. If you declare only a signature (L40), your implementation must be outside the class.

Line 149: You declare an object named day_of_year and pass number to it's constructor. That's fine. Line 150: You're try to call the object you just created. What are you trying to do here? Remove this line.

Edit: Corrected typo. "destructor" should have been "constructor".

[ocKiNOsIi]

I've tried to make my code less confusing

I have Set Day done..( case d inside case s)

can someone show me how to print out the week like this

Mon Jun 14, 2021; Tue Jun 15, 2021; Wed Jun 16, 2021; Thr Jun 17, 2021; Fri Jun 18, 2021; Sat Jun 19, 2021; Sun Jun 20, 2021

#include <string>
#include <iostream>
using std::string;
using namespace std;

template<typename T> // useful for getting user's keyboard input without crash or hang
T kbd_input(const string &prompt="Enter: ", const string &errmsg="  Oops! Try again.\n\n") {
  while (true) {
    cout << prompt; T ans{};
    if (cin>>ans) return ans;
    else {
      cin.clear(); cin.ignore(INT_MAX, '\n'); cout<<errmsg;
    }
  }
}


class DayOfYear
{
private:
    const static string monthOfYear[12];
    const static int daysInYear[12];
    const static int daysInMonth[12];
        
    string month;            // To hold a month name
    int day;                    // To hold a day
    int arrayIdx;            // Stores an array index
    int year;

    public:
        DayOfYear()
        { }

        DayOfYear(int d);
        DayOfYear(string, int);
        
        bool isMonthName(string);
        void setMonth(int);
        void helpIncrement();
        void helpDecrement();
        void print();

        string getMonth() const
        { return month; }

        int getDay() const
        { return day; }
    
    int getYear() const
    { return year; }

        DayOfYear operator++();
        DayOfYear operator++(int);
        DayOfYear operator--();
        DayOfYear operator--(int);
};


// Definition of const static array member holding month names
const string DayOfYear::monthOfYear[12] = { "January", "February", "March", "April", "May", "June", "July",
                                                      "August", "September", "October", "November", "December" };

// Definition of const static array member holding a range of days
const int DayOfYear::daysInYear[12] = { 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
const int DayOfYear::daysInMonth[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

//
DayOfYear::DayOfYear(int d)
{
    if (d >= 1 && d <= 365)
    {
        setMonth(d);

        if (d > 31)
        {
            d %= daysInYear[arrayIdx-1];
        }
        day = d;
    }
    else
    {
        cout << "\nInput failure: A normal year has at least 1 and no more than 365 days.\n";
    }
}

//
DayOfYear::DayOfYear(string m, int d)
{
    if (isMonthName(m) == true)
    {
        month = m;
    }
    else
    {
        cout << "\nInput failure: " << m << " does not exist\n";
        cout << "Please restart this program and try again!";
        cin.get();
        cin.ignore();
        exit(0);
    }
    
    if (d >= 1 && d <= daysInMonth[arrayIdx])
    {
        day = d;
    }
    else
    {
        cout << "\nInput failure: " << month << " starts with the 1.st, and has "
              << daysInMonth[arrayIdx] << " days.\n";
        cout << "Please restart this program and try again!";
        cin.get();
        cin.ignore();
        exit(0);
    }
}

//
void DayOfYear::setMonth(int d)
{
    bool isFound = false;

    for (int count = 0; count < 12 && isFound != true; count++)
    {
        if (d <= daysInYear[count])
        {
            arrayIdx = count;
            month = monthOfYear[count];
            
            isFound = true;
        }
    }
}

//
bool DayOfYear::isMonthName(string m)
{
    for (int count = 0; count < 12; count++)
    {
        if (m == monthOfYear[count])
        {
            arrayIdx = count;
            return true;
        }
    }
    return false;
}


//
void DayOfYear::print()
{
    cout << getMonth() << " " << getDay() << ", 2021";
}


int main()
{
    int day = 0;
  cout <<"Welcome to ??????s calendar helper!\n";
 // Day day; // this is updated in the set day options, and is the 1st day displayed in the Display options.
  for (bool running=true; running; ) {
    cout<<"\nOptions: Display d)ay w)eek m)onth; s)et-day t)esting q)uit: ";
    string option; char option_letter; cin>>option; option_letter=tolower(option[0]);
    switch (option_letter) {
      case 's': // set day, test constructors: Day(), Day(int) constructor
        {
          char option = tolower(kbd_input<char>("  set day d)efault m)month,day n)umber v)ary: "));
          if (option=='q') break;
          
          switch(option) {
            case 'd': {
              cout<<"    set day d option - TO BE IMPLMENTED\n";
                cout << "Enter a day in the range of 1 through 365:\n";
                cin >> day;
                DayOfYear dayTwo(day);
                dayTwo.print();
              break;
            }
            
            case 'm': {
              cout<<"    set day m option - TO BE IMPLMENTED\n";
              break;
            }

            case 'n': {
              cout<<"    set day n option - TO BE IMPLMENTED\n";
              break;
            }
            
            case 'v': {
              cout<<"    set day v option - TO BE IMPLMENTED\n";
              break;
            }

            default:
              cout<<"    set day Invalid option.\n"; break;// continue;
          }
          // cout<<"  day#=["<<day<<"] "<<day.to_string()<<endl; // generic output. Could be helpful.
          break;
        } // case 's' for set day
        
      case 'd': {

          // Create a second DayOfYear object to demonstrate the overloaded pre- and postfix -- operators
          DayOfYear dayTwo(day);
          dayTwo.print();

          cout << endl;
          break;
        }
        
      case 'm': {
          cout<<"m option - show a month, TO BE IMPLMENTED\n";
          break;
        }
        
      case 'w': {
          cout<<"w option - show a week, TO BE IMPLMENTED\n";
          break;
        }
        
      case 't': {
          cout<<"t option - test increment, decrement operators, TO BE IMPLMENTED\n";
          break;
        }
        
      case 'q':
        running=false;
        break;
        
      default:
        cout<<"  Invalid option, try again. q to quit.\n";
        break;
    }
  }
  cout<<"\nThanks for using ??????s calendar helper! Good-bye!";
}