Thread: Help simplifying huge nested if statement?

This is a programming project from a textbook, and it executes as intended. However, I can't help but thinking there are ways to simplify the code because the if statement I am using is massive, with nested if statements inside.

Any ideas on simplifying this code? Or any ideas on alternatives to the if statement I am using?

(The program is to convert 24-hour time into 12-hour time, and the jpb package is needed to use the SimpleIO class.)

// the jpb package needed to use the SimpleIO class
import jpb.*;
 
public class equivalent12HourTime
{
	public static void main(String[] args)
	{
		// hh:mm user input
		SimpleIO.prompt("\nEnter a 24-hour time\n  in military hh:mm format\n   (example: 21:11 --> 11:11 p.m.) : ");
		String hh_mm = SimpleIO.readLine();
 
		// int hour
		String hh = hh_mm.substring(0, 2);
		int hour = Integer.parseInt(hh);
 
		// int minutes
		String mm = hh_mm.substring(3);
		int minutes = Integer.parseInt(mm);
 
		/* ginormous nested if statement:
		   1. checks minutes for errors,
		   2. checks hours for errors,
		   3. converts 24-hour into 12-hour format and prints */
		if ( (minutes <= 0) || (minutes >= 60) )
		{
			System.out.println("\nIncorrect time entered, please try again.");
		}
		else
		{
			if ( (hour > 0) && (hour <= 12) )
			{
				if (hour == 12)
				{
					System.out.println("\nEquivalent 12-hour time: " + hour + ":" + minutes + " p.m.");
				}
				else
				{
					System.out.println("\nEquivalent 12-hour time: " + hour + ":" + minutes + " a.m.");
				}
			}
			else if ( (hour > 12) && (hour <= 24) )
			{
				if (hour == 24)
				{
					System.out.println("\nEquivalent 12-hour time: " + (hour - 12) + ":" + minutes + " a.m.");
				}
				else
				{
					System.out.println("\nEquivalent 12-hour time: " + (hour - 12) + ":" + minutes + " p.m.");
				}
			}
			else
			{
				System.out.println("\nIncorrect time entered, please try again.");
			}
		} // end of if statement
	}
}

In my opinion, there is no better solution than if statement in this situation.

Hey thanks folks. Kevin -- what do you mean by splitting it up into methods more? Would this be to separate the information into categories for readability? (I'm thinking for the above code two separate methods for a.m. and p.m.?)

and please reply to another question here if you have the time --
http://www.javaprogrammingforums.com...i-am-noob.html
(I am having a lot of trouble with simple 2D animation right now)