Augment the time class referred to in Exercise 3 to include overloaded increment (++) and decrement (--) operators that operate in both prefix and postfix notation and return values. Add statements to main() to test these operators.

 

SOLUTION:

#include "stdafx.h"

#include "iostream"

using namespace std;

/////////////////////////////////////////////////////////////////////////////////////////

class time

{           private:

                        int hrs, mints, secs;

            public:

                        time( ) : hrs(0), mints(0), secs(0)

                                    { /*Empty Body*/ }

                        time(int h, int m, int s) : hrs(h), mints(m), secs(s)

{ /*Empty Body*/ }

                        void display( ) const

                                     {          cout << hrs << ":" << mints << ":" << secs << endl;              }

                        time operator ++ ( );

                        time operator ++ (int);

                        time operator -- ( );

                        time operator -- (int);

};

//---------------------------------------------------------------------------------------

time time::operator ++ ( )

{

            ++secs;

            if(secs > 59)

                        {           secs -=60;       mints++;          }

            if(mints > 59)

                        {           mints -=60;      hrs++;              }

            return time(hrs, mints, secs); 

}

time time::operator ++ (int)

{

            secs++;

            if(secs > 59)

                        {           secs -=60;       mints++;          }

            if(mints > 59)

                        {           mints -=60;      hrs++;              }

            return time(hrs, mints, secs); 

}

time time::operator -- ( )

{

            --secs;

            if(secs < 0)

                        {           secs +=60;      mints--;            }

            if(mints < 0)

                        {           mints +=60;     hrs--;                }

            return time(hrs, mints, secs); 

}

time time::operator -- (int)

{

            secs--;

            if(secs < 0)

                        {           secs +=60;      mints--;            }

            if(mints < 0)

                        {           mints +=60;     hrs--;                }

            return time(hrs, mints, secs); 

}

/////////////////////////////////////////////////////////////////////////////////////////

void main( )

{

            time time1(10,25,2), time2(5,59,58);

            cout << "Time1 is: ";               time1.display( );

            cout << "Time2 is: ";               time2.display( );

            ++time1;          cout << "\nTime1 after prefix increment is: ";            time1.display( );

            ++time2;          cout << "Time2 after prefix increment is: ";               time2.display( );

            time1++;          cout << "\nTime1 after postfix increment is: ";           time1.display( );

            time2++;          cout << "Time2 after postfix increment is: ";              time2.display( );

            --time1;            cout << "\nTime1 after prefix decrement is: ";           time1.display( );

            --time2;            cout << "Time2 after prefix decrement is: ";              time2.display( );

            time1--;            cout << "\nTime1 after postfix decrement is: ";          time1.display( );

            time2--;            cout << "Time2 after postfix decrement is: ";             time2.display( );

            system("pause");

}

OUTPUT:

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