adding the date class files

lectures/03_classes_I/date.cpp

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+// File:    date.cpp
+// Purpose: Implementation file for the Date class.
+
+#include <iostream>
+#include "date.h"
+
+// array to figure out the number of days, it's used by the auxiliary function daysInMonth
+const int DaysInMonth[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+
+Date::Date() {	//default constructor
+  day = 1;
+  month = 1;
+  year = 1900;
+}
+
+Date::Date(int aMonth, int aDay, int aYear) { // construct from month, day, & year
+  month = aMonth;
+  day = aDay;
+  year = aYear;
+}
+
+
+int Date::getDay() const {
+  return day;
+}
+
+int Date::getMonth() const {
+  return month;
+}
+	
+int Date::getYear() const {
+  return year;
+}
+
+void Date::setDay(int d) {
+  day = d;
+}
+
+void Date::setMonth(int m) {
+  month = m;
+}
+
+void Date::setYear(int y) {
+  year = y; 
+}
+
+void Date::increment() {
+  if (!isLastDayInMonth()) {
+    day++; 
+  } else {
+    day = 1;
+    if (month == 12) {  // December
+      month = 1;
+      year++;
+    } else {
+      month++;
+    }
+  }
+}
+
+bool Date::isEqual(const Date& date2) const {
+  return day == date2.day && month == date2.month && year == date2.year;
+}
+
+bool Date::isLeapYear() const {
+  return (year%4 ==0 && year % 100 != 0) || year%400 == 0;
+}
+
+int Date::lastDayInMonth() const {
+  if (month == 2 && isLeapYear())
+    return 29;
+  else
+    return DaysInMonth[ month ];    
+}
+
+bool Date::isLastDayInMonth() const {
+  return day == lastDayInMonth();   // uses member function
+}
+
+void Date::print() const {
+  std::cout << month << "/" << day << "/" << year;
+}
+
+bool sameDay(const Date& date1, const Date& date2) {
+  return date1.getDay() == date2.getDay() && date1.getMonth() == date2.getMonth();
+}

lectures/03_classes_I/date.h

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+// File:     date.h
+// Purpose:  Header file with declaration of the Date class, including
+//   member functions and private member variables.
+
+class Date {
+public:
+  Date();
+  Date(int aMonth, int aDay, int aYear);
+
+  // ACCESSORS
+  int getDay() const;
+  int getMonth() const;
+  int getYear() const;
+
+  // MODIFIERS
+  void setDay(int aDay);
+  void setMonth(int aMonth);
+  void setYear(int aYear);
+  void increment();
+
+  // other member functions that operate on date objects
+  bool isEqual(const Date& date2) const;  // same day, month, & year?
+  bool isLeapYear() const;     
+  int lastDayInMonth() const;
+  bool isLastDayInMonth() const;
+  void print() const;                     // output as month/day/year
+
+private:  // REPRESENTATION (member variables)
+  int day;
+  int month;
+  int year;
+};
+
+// prototypes for other functions that operate on class objects are often
+// included in the header file, but outside of the class declaration
+bool sameDay(const Date &date1, const Date &date2); // same day & month?

lectures/03_classes_I/date_main.cpp

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+// Program:  date_main.cpp
+// Purpose:  Demonstrate use of the Date class.
+
+#include <iostream>
+#include "date.h"
+
+int main() {
+  std::cout << "Please enter today's date.\n"
+	    << "Provide the  month, day and year: ";
+  int month, day, year;
+  std::cin >> month >> day >> year;
+  Date today(month, day, year);
+
+  //Let's show what happens if we try to use today.month (private member variable)
+  Date tomorrow(today.getMonth(), today.getDay(), today.getYear());
+  tomorrow.increment();
+  
+  std::cout << "Tomorrow is ";
+  tomorrow.print();
+  std::cout << std::endl;
+
+  Date Sallys_Birthday(9,29,1995);  
+  if (sameDay(tomorrow, Sallys_Birthday)) {
+    std::cout << "Hey, tomorrow is Sally's birthday!\n";
+  }
+
+  std::cout << "The last day in this month is " << today.lastDayInMonth() << std::endl;
+  return 0;
+}