Problem with scanning char

[danthegreat]

Excerpt of my program:

System.out.print("Next customer (y/n): ");
		again=Keyboard.nextLine().charAt(0);

		if(again=='y'){
			num=1;
			
		}
		else if(again=='n'){
			System.out.print("Thank you for using Floppy Systems.");
			System.exit(-1);
			
		}
		
		}while(num==1);

Next customer (y/n): Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 0
	at java.lang.String.charAt(String.java:686)
	at DanielHello.main(DanielHello.java:27)

I get that error stating that my string index is out of range? How is that possible? if the user enters 'y' then shouldn't that be at a string index of 0? Eclipse doesn't let me enter in anything at all when I debug

[Fubarable]

It's hard to say what the problem is based on the information at hand, but this suggests that your String has no characters in it. Perhaps prior to this code block, you've used the Scanner object to get a next() or nextInt() and did not also take care to swallow the end of line token with a nextLine() call, but I'm just guessing.

[danthegreat]

This is the full program:

import java.util.*;
public class DanielHello {
	
	public static void main(String[] args){
	
		final double unit = .26;
		Scanner Keyboard = new Scanner(System.in);
		

		char again;
		int num = 0;
		do{
		
		System.out.print("Enter Quantity: ");
		int quantity = Keyboard.nextInt();
		
		if(quantity%25==0){
			System.out.println("You have ordered " + quantity + " Floppies --- $" + quantity*unit);
			
		}
		else if(quantity%25!=0){
			System.out.println("Floppies can only be ordered in packs of 25.");
			
		}
		
		System.out.print("Next customer (y/n): ");
		again=Keyboard.nextLine().charAt(0);

		if(again=='y'){
			num=1;
			
		}
		else if(again=='n'){
			System.out.print("Thank you for using Floppy Systems.");
			System.exit(-1);
			
		}
		
		}while(num==1);
		

		
	}

}

[Fubarable]

This is the full program:

Well I guess it was a good guess on my part!

You do in fact call nextInt() prior to your code above:

		System.out.print("Enter Quantity: ");
		int quantity = Keyboard.nextInt();

and you don't handle the end of line token which is messing up your scanner. The solution is to handle that token with a nextLine() call:

		System.out.print("Enter Quantity: ");
		int quantity = Keyboard.nextInt();
		Keyboard.nextLine(); // swallow the end of line token

Also, you'll not want to capitalize the first letter of variables but only classes, interfaces, enums and the like so as not to confuse those helping you or grading you.

[sunde887]

As Fubar eluded to, you called nextInt and then nextLine, which causes problems due to not swalling the eol. Two suggestions:
1) Add Keyboard.nextLine(); after calls to nextInt(), nextDouble() and similar methods.
2) Only read lines at a time and parse the number with Integer.parseInt(String s)
int quantity = Integer.parseInt(Keyboard.nextLine());

Either approach will work well enough.

Edit: Too slow :(