// timeclass2.cc
#include <iostream>
#include <sstream>    // for stringstream below
#include <string>
using namespace std;

class Time
{
  private:
    int Hours;   // 0 to 23
    int Minutes; // 0 to 59
    string StringForm; // time converted to a string

  public:
    Time() {
      Hours = Minutes = 0;
    }
    Time(int hrs, int mins)
      :Hours(hrs),Minutes(mins) {
    } 
    void printTime() {
      cout << Hours << " hours and " << Minutes << " minutes" << endl;
    }
    // do any rollovers necessary on hours or minutes
    void TimeCheck() {
      if (Minutes > 59) {
        Minutes = 0; ++Hours;
      }
      if (Minutes < 0) {
        Minutes = 59; --Hours;
      }
      if (Hours > 23) Hours = 0;
      if (Hours < 0) Hours = 23;
    }
    // prefix ++ operator, i.e., ++myTime
    Time& operator ++ () {
      ++Minutes; TimeCheck();
      return *this; // don't want to make a new object
    }
    // prefix -- operator, i.e., --myTime
    Time& operator -- () {
      --Minutes; TimeCheck();
      return *this; // don't want to make a new object
    }
    // postfix ++ operator, i.e., myTime++
    // here we need to return the state before increment
    Time operator ++ (int) {
      Time TmpTime(Hours, Minutes); // make a backup
      ++Minutes; TimeCheck();
      return TmpTime; 
    }
    // postfix -- operator, i.e., myTime--
    // here we need to return the state before decrement
    Time operator -- (int) {
      Time TmpTime(Hours, Minutes); // make a backup
      --Minutes; TimeCheck();
      return TmpTime; 
    }
    operator const char*() {
      ostringstream out;         // stringstream lets us build strings
      out << Hours << ":" << Minutes;
      StringForm = out.str();    // hold this as member data so it and the
                                 // char* to it won't disappear at end
                                 // of this function
      return StringForm.c_str(); // get C-style const char* from string
    }
};

int main()
{
  Time T1(0, 0);
  --T1;
  cout << "Time is " << T1 << endl;
}