How to make my clock like this 03:05:01

Question

I have project in java.

Create CTime class with the following specifications

1. Attributes: Hour, minute and second
2. Hour >=0 and <= 23, minute >=0 and <=59 , second >=0 and <= 59
3. Methods
   • Constructor that updates the CTime attributes
   • set and get methods for each attribute
   • tick method that add 1 second to the CTime object and returns nothing
   • toString method that creates time string with the following format HH:mm:ss e.g. 22:15:01

and I did this

public class CTime {

    int hour;
    int min;
    int sec;

    public CTime(int h, int m, int s) {
        hour = h;
        min = m;
        sec = s;
    }

    public void setHour(int h) {
        hour = h;
    }

    public int getHour() {
        return hour;
    }

    public void setMin(int m) {
        min = m;
    }

    public int getMin() {
        return min;
    }

    public void setSec(int s) {
        sec = s;
    }

    public int getSec() {
        return sec;
    }

    public void tick() {
        sec++;
        if (sec >= 59) {
            sec = 0;
            min++;
            if (min >= 59) {
                min = 0;
            }
            hour++;
        }
    }

    public String toString() {
        String s = hour + ":" + min + ":" + sec;
        return s;
    }
}

How to make my hour and min and sec with 2 digit, e.g. 05:02:09?

And my code is it correct or not?

Answer 1

If you insist on doing this kind of stuff with Strings the way you are, you could do something like the following:

public String toString() {
    String s =  (hour > 9 ? hour : "0" + hour) + ":" + (min > 9 ? min : "0" + min) + ":" + (sec > 9 ? sec : "0" + sec);
    return s;
}

Answer 2

Just use String.format()

public String toString() {
    String s = String.format("%02d:%02d:%02d", hour, min, sec);
    return s;
}

One more link here

And your code, yes it is correct. To make it a live clock, all you have to do is call tick() method every second. Take a look at this SO post to learn how to do that.