Oi galera, o código em baixo funciona direitinho, com pre-inicialização. O problema que eu estou tendo é como faço para implementar 
● método que imprime a instancia em formato de 12 horas (AM/ PM)
● previousSecond()
● nextMinute()
● previousMinute()
● nextHour()
● previousHour()
 
 
/* Test Driver for the Time class */ #include <iostream> #include "Time.h"    // include header of Time class using namespace std; int main() {     Time t_2;     int minut;     int seg;     int hor;     cout<< "\n Informe a hora: ";     cin>>hor;     t_2.setHour(hor);     cout<< "\n Informe o minuto: ";     cin>>minut;     t_2.setMinute(minut);     cout<< "\n Informe o segundo: ";     cin>>seg;     t_2.setSecond(seg);    cout<<"Object t1 state: \n";    cout << "Hour is "   << t_2.getHour()   << endl;    cout << "Minute is " << t_2.getMinute() << endl;    cout << "Second is " << t_2.getSecond() << endl;    return 0; } //======================================================================================= /* Header for the Time class (Time.h) */ #ifndef TIME_H   // Include this "block" only if TIME_H is NOT defined #define TIME_H   // Upon the first inclusion, define TIME_H so that                  //  this header will not get included more than once class Time { private:  // private section    // private data members    int hour;     // 0 - 23    int minute;   // 0 - 59    int second;   // 0 - 59 public:   // public section    // public member function prototypes    //Time(int h = 0, int m = 0, int s = 0);        // Constructor with default values    int getHour() const;                                   // public getter for private data member hour    void setHour(int h);                                  // public setter for private data member hour    int getMinute() const;                             // public getter for private data member minute    void setMinute(int m);                           // public setter for private data member minute    int getSecond() const;                          // public getter for private data member second    void setSecond(int s);                          // public setter for private data member second    void setTime(int h, int m, int s);        // set hour, minute and second    void print() const;                               // Print a description of this instance in "hh:mm:ss"    void nextSecond();                            // Increase this instance by one second };                                                             // need to terminate the class declaration with a semicolon #endif  // end of "#ifndef" block //====================================================================================== /* Implementation for the Time Class (Time.cpp) */ #include <iostream> #include <iomanip> #include "Time.h"    // include header of Time class using namespace std; // Constructor with default values. No input validation /*Time::Time(int h, int m, int s) {    hour = h;    minute = m;    second = s; } */ // public getter for private data member hour int Time::getHour() const {    return hour; } // public setter for private data member hour. No input validation void Time::setHour(int h) {    hour = h; } // public getter for private data member minute int Time::getMinute() const {    return minute; } // public setter for private data member minute. No input validation void Time::setMinute(int m) {    minute = m; } // public getter for private data member second int Time::getSecond() const {    return second; } // public setter for private data member second. No input validation void Time::setSecond(int s) {    second = s; } // Set hour, minute and second. No input validation void Time::setTime(int h, int m, int s) {    hour = h;    minute = m;    second = s; } // Print this Time instance in the format of "hh:mm:ss", zero filled void Time::print() const {    cout << setfill('0');    // zero-filled, need <iomanip>, sticky    cout << setw(2) << hour  // set width to 2 spaces, need <iomanip>, non-sticky         << ":" << setw(2) << minute         << ":" << setw(2) << second << endl; } // Increase this instance by one second void Time::nextSecond() {    ++second;    if (second >= 60) {       second = 0;       ++minute;    }    if (minute >= 60) {       minute = 0;       ++hour;    }    if (hour >= 24) {       hour = 0;    } }  
 
 
 
 
Desde já obrigado