C program to design a digital clock code example

Example: C program to design a digital clock

#include <stdio.h>
#include <time.h>//for sleep() function
#include <unistd.h>
#include <stdlib.h>
int main()
{
int hour, minute, second;
hour=minute=second=0;
while(1)
{
//clear output screen
system("clear");
//print time in HH : MM : SS format
printf("%02d : %02d : %02d ",hour,minute,second);
//clear output buffer in gcc
fflush(stdout);
//increase second
second++;
//update hour, minute and second
if(second==60){
minute+=1;
second=0;
}
if(minute==60){
hour+=1;
minute=0;
}
if(hour==24){
hour=0;
minute=0;
second=0;
}
sleep(1);   //wait till 1 second
}
return 0;
}