sleeper.cpp

// CPP program to create a timer 
#include <iomanip> 
#include <iostream> 
#include <stdlib.h> 
#include <unistd.h> 
using namespace std; 
  
// hours, minutes, seconds of timer 
int hours = 0; 
int minutes = 0; 
int seconds = 0; 
  
// function to display the timer 
void displayClock() 
{ 
    // system call to clear the screen 
    //system("clear"); 
  
    cout << setfill(' ') << setw(55) << "         TIMER         \n"; 
    cout << setfill(' ') << setw(55) << " --------------------------\n"; 
    cout << setfill(' ') << setw(29); 
    cout << "| " << setfill('0') << setw(2) << hours << " hrs | "; 
    cout << setfill('0') << setw(2) << minutes << " min | "; 
    cout << setfill('0') << setw(2) << seconds << " sec |" << endl; 
    cout << setfill(' ') << setw(55) << " --------------------------\n"; 
} 
  
void timer() 
{ 
    // infinte loop because timer will keep  
    // counting. To kill the process press 
    // Ctrl+D. If it does not work ask 
    // ubuntu for other ways. 
    while (true) { 
          
        // display the timer 
        displayClock(); 
  
        // sleep system call to sleep  
        // for 1 second 
        sleep(30); 
  
        // increment seconds 
        seconds++; 
  
        // if seconds reaches 60 
        if (seconds == 60) { 
          
            // increment minutes 
            minutes++; 
  
            // if minutes reaches 60 
            if (minutes == 60) { 
          
                // increment hours 
                hours++; 
                minutes = 0; 
            } 
            seconds = 0; 
        } 
    } 
} 
  
// Driver Code 
int main() 
{ 
    // start timer from 00:00:00 
    timer(); 
    return 0; 
}