java - 如何让我的时钟像这样 03 :05:01

Question

我有一个java项目。

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

我做到了

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;
    }
}

如何用 2 位数字表示小时、分钟和秒，例如05:02:09？

我的代码是否正确？

Answer 1

如果你坚持用字符串做这种事情，你可以这样做:

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