Answer 1

A class is an abstract data type, where you define your data (properties) and your functions (methods) as its members that can be accessed by the three access specifiers private, protected or public, (access is private by default). Classes are not objects, they are used to instantiate objects.

// DateClass.cc
// Program to demonstrate the definition of a simple class
// and member functions

#include <iostream>
using namespace std;

// Declaration of Date class
class Date {

public:
Date(int, int, int);
void set(int, int, int);
void print();

private:
int year;
int month;
int day;
};

int main()
{
// Declare today to be object of class Date
// Values are automatically intialised by calling constructor function
Date today(1,9,1999);

cout << "This program was written on ";
today.print();

cout << "This program was modified on ";
today.set(5,10,1999);
today.print();

return 0;
}

// Date constructor function definition
Date::Date(int d, int m, int y) //Function of class Date
{
if(d>0 && d<31) day = d;
if(m>0 && m<13) month = m;
if(y>0) year =y;
}

// Date member function definitions
void Date::set(int d, int m, int y) //Function of class Date
{
if(d>0 && d<31) day = d;
if(m>0 && m<13) month = m;
if(y>0) year =y;
}

void Date::print() //Function of class Date
{
cout << day << "-" << month << "-" << year << endl;
}