Java - Adding a 0 in the minutes of the current time (GMT)

Question

when I output the following code (taken from dr. Liang Introduction to Java, 10th ed., chapter 03 - selections)

/*
(Current time) Listing 2.7, ShowCurrentTime.java, gives a program that displays
the current time in GMT. Revise the program so that it prompts the user to enter
the time zone offset to GMT and displays the time in the specified time zone.
*/


import java.util.Scanner;

public class Ex_03_08 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

         System.out.print("Enter the time zone (GMT): ");
        int gmt = input.nextInt();

         long totalMilliseconds = System.currentTimeMillis();

         long totalSeconds = totalMilliseconds / 1000;

         long currentSecond = totalSeconds % 60;

         long totalMinutes = totalSeconds / 60;

         long currentMinute = totalMinutes % 60;

         long totalHours = totalMinutes / 60;

         long currentHour = totalHours % 24;
        currentHour = currentHour + gmt;

         System.out.println("The current time is " + currentHour + ":"
                + currentMinute + ":" + currentSecond);

        input.close();
    }
}

the output is

Enter the time zone (GMT): 1
The current time is 11:2:31

How can I let display instead 11:02:31?

Thank you.

score 3 · Accepted Answer · answered Nov 18 '16 at 10:10

You can do something like this,

String currentMinuteStr=""+currentMinute ;
if(currentMinuteStr.length()==1){
currentMinuteStr="0"+currentMinuteStr;
}

I have just converted the minutes variable to string and then checked whether the length of the string is 1 that is whether it is a one digit minute and then i have appended the existing minutes to 0 and then you can display it as before like this,

System.out.println("The current time is " + currentHour + ":"
            + currentMinuteStr+ ":" + currentSecond);

score 1 · Answer 2 · edited Sep 25 '17 at 07:58

You can format your input in C style printf using format method.

class NumericFormat
{
    public static void main(String[] args) {
        System.out.format("%02d%n",3);
        //you can use \n too but %n is preferrable for format method
    }
}

Get a better understanding at Java Docs

If link fails, here are some of the formatters.

On a side Note, to format and use Date and Time, Java 8 has clean inbuilt API. Get a look at this Oracle tutorial - Date Time Parsing and Formatting

score 0 · Answer 3 · answered Nov 18 '16 at 10:25

     long totalMilliseconds = System.currentTimeMillis();

     long totalSeconds = totalMilliseconds / 1000;

     long currentSecond = totalSeconds % 60;

     long totalMinutes = totalSeconds / 60;

     long currentMinute = totalMinutes % 60;

     long totalHours = totalMinutes / 60;

     long currentHour = totalHours % 24;
     currentHour = currentHour + gmt;

     String strTime = "" + (currentHour < 10 ? "0" + currentHour : currentHour) +
         (currentMinute < 10 ? "0" + currentMinute : currentMinute) +
         (currentSecond < 10 ? "0" + currentSecond : currentSecond);

     System.out.println("The current time is : " + strTime);

Java - Adding a 0 in the minutes of the current time (GMT)

3 Answers3