Thread: Problem with String (and integer) conversion!

The program below shows an array of "crayons". The user should be able to enter a number between 1-8 and show the appropriate crayon. Also, when the user type "end", it should terminate the program. My problem is that it ends the program when I type "end", but it's giving me the error. Since my variable is a String, to show the array, I've converted it to an integer using Integer.parseInt() method.

The error:

Exception in thread "main" java.lang.NumberFormatException: For input string: "end"
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
	at java.lang.Integer.parseInt(Integer.java:492)
	at java.lang.Integer.parseInt(Integer.java:527)
	at Crayon.main(Crayon.java:32)
Java Result: 1

Result:

Color: Red 		Length in mm: 16 	Sharpness: 1
Color: Yellow 		Length in mm: 17 	Sharpness: 4
Color: Green 		Length in mm: 10 	Sharpness: 2
Color: Blue 		Length in mm: 11 	Sharpness: 5
Color: Brown 		Length in mm: 16 	Sharpness: 1
Color: Black 		Length in mm: 23 	Sharpness: 2
Color: Orange 		Length in mm: 29 	Sharpness: 3
Color: Purple 		Length in mm: 17 	Sharpness: 4
Which crayon you like to see? (1-8) 3
That crayon is Color: Green 		Length in mm: 10 	Sharpness: 2
Color: Red 		Length in mm: 16 	Sharpness: 1
Color: Yellow 		Length in mm: 17 	Sharpness: 4
Color: Green 		Length in mm: 10 	Sharpness: 2
Color: Blue 		Length in mm: 11 	Sharpness: 5
Color: Brown 		Length in mm: 16 	Sharpness: 1
Color: Black 		Length in mm: 23 	Sharpness: 2
Color: Orange 		Length in mm: 29 	Sharpness: 3
Color: Purple 		Length in mm: 17 	Sharpness: 4
Which crayon you like to see? (1-8) end
Exception in thread "main" java.lang.NumberFormatException: For input string: "end"
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
	at java.lang.Integer.parseInt(Integer.java:492)
	at java.lang.Integer.parseInt(Integer.java:527)
	at Crayon.main(Crayon.java:32)
Java Result: 1

Code:

import java.util.Scanner;
import java.util.Random;
 
public class Crayon {
 
    public static void main(String[] args) {
 
        Scanner scan = new Scanner(System.in);
        Random rand = new Random();
        String choice;
 
        choice = "";
 
        String[]crayon = {"Color: Red \t\tLength in mm: 16 \tSharpness: 1",
                          "Color: Yellow \t\tLength in mm: 17 \tSharpness: 4",
                          "Color: Green \t\tLength in mm: 10 \tSharpness: 2",
                          "Color: Blue \t\tLength in mm: 11 \tSharpness: 5",
                          "Color: Brown \t\tLength in mm: 16 \tSharpness: 1",
                          "Color: Black \t\tLength in mm: 23 \tSharpness: 2",
                          "Color: Orange \t\tLength in mm: 29 \tSharpness: 3",
                          "Color: Purple \t\tLength in mm: 17 \tSharpness: 4",}; 
 
        while(!choice.equals("end"))
        {
            for(int a=0; a<crayon.length; a++)
            {
                System.out.println(crayon[a]);
            }
 
            System.out.print("Which crayon you like to see? (1-8) ");
            choice = scan.nextLine();            
            System.out.println("That crayon is " + crayon[Integer.parseInt(choice) - 1]);        
        }
    }
}

Originally Posted by Norm

Check the value of choice for "end" before trying to convert it to an int.

I'm sorry, but not sure if I understand.

Thank you so much, it works now

Result:

run:
Color: Red 		Length in mm: 16 	Sharpness: 1
Color: Yellow 		Length in mm: 17 	Sharpness: 4
Color: Green 		Length in mm: 10 	Sharpness: 2
Color: Blue 		Length in mm: 11 	Sharpness: 5
Color: Brown 		Length in mm: 16 	Sharpness: 1
Color: Black 		Length in mm: 23 	Sharpness: 2
Color: Orange 		Length in mm: 29 	Sharpness: 3
Color: Purple 		Length in mm: 17 	Sharpness: 4
Which crayon you like to see? (1-8) type [end] to terminate 1
That crayon is Color: Red 		Length in mm: 16 	Sharpness: 1
Color: Red 		Length in mm: 16 	Sharpness: 1
Color: Yellow 		Length in mm: 17 	Sharpness: 4
Color: Green 		Length in mm: 10 	Sharpness: 2
Color: Blue 		Length in mm: 11 	Sharpness: 5
Color: Brown 		Length in mm: 16 	Sharpness: 1
Color: Black 		Length in mm: 23 	Sharpness: 2
Color: Orange 		Length in mm: 29 	Sharpness: 3
Color: Purple 		Length in mm: 17 	Sharpness: 4
Which crayon you like to see? (1-8) type [end] to terminate 2
That crayon is Color: Yellow 		Length in mm: 17 	Sharpness: 4
Color: Red 		Length in mm: 16 	Sharpness: 1
Color: Yellow 		Length in mm: 17 	Sharpness: 4
Color: Green 		Length in mm: 10 	Sharpness: 2
Color: Blue 		Length in mm: 11 	Sharpness: 5
Color: Brown 		Length in mm: 16 	Sharpness: 1
Color: Black 		Length in mm: 23 	Sharpness: 2
Color: Orange 		Length in mm: 29 	Sharpness: 3
Color: Purple 		Length in mm: 17 	Sharpness: 4
Which crayon you like to see? (1-8) type [end] to terminate end
BUILD SUCCESSFUL (total time: 6 seconds)

New Code:

import java.util.Scanner;
import java.util.Random;
 
public class Crayon {
 
    public static void main(String[] args) {
 
        Scanner scan = new Scanner(System.in);
        Random rand = new Random();
        String choice;
 
        choice = "";
 
        String[]crayon = {"Color: Red \t\tLength in mm: 16 \tSharpness: 1",
                          "Color: Yellow \t\tLength in mm: 17 \tSharpness: 4",
                          "Color: Green \t\tLength in mm: 10 \tSharpness: 2",
                          "Color: Blue \t\tLength in mm: 11 \tSharpness: 5",
                          "Color: Brown \t\tLength in mm: 16 \tSharpness: 1",
                          "Color: Black \t\tLength in mm: 23 \tSharpness: 2",
                          "Color: Orange \t\tLength in mm: 29 \tSharpness: 3",
                          "Color: Purple \t\tLength in mm: 17 \tSharpness: 4",}; 
 
        while(!choice.equals("end"))
        {
            for(int a=0; a<crayon.length; a++)
            {
                System.out.println(crayon[a]);
            }
 
            System.out.print("Which crayon you like to see? (1-8) type [end] to terminate ");
            choice = scan.nextLine();          
 
            //If string is not "end" then convert string to int 
 
            if(!choice.equals("end"))
            {
                System.out.println("That crayon is " + crayon[Integer.parseInt(choice) - 1]);  
            }   
        }
    }
}