Thread: Can Anyone Help With Arrays?

I am attempting to design and implement a program with a Java class that will ask the user to input a non-null string. First, I should convertthis string to lower case (for simplicity) and store each character of the string into a char[] (an array of type char) (“helloworld”→|h|e|l|l|o|w|o|r|l|d|). Then print the array in forward and reverse order, unless the input string is a palindrome (the same spelling forward and backward, ex: "noon”). In that case, only print the array once and state that the inputted string is a planindrome. (see sample output). Next, store the string into a different char[], putting only 1 instance of each character into the array (“helloworld”→|h|e|l|o|w|r|d|). Then printthe new array in forward and reverse order (see sample output). Finally, I should sort the new array containing the non-repeated characters in ascending alphabetical order (|h|e|l|o|w|r|d|→|d|e|h|l|o|r|w|). Then print the sorted array in forward and reverse order ( see sampleoutput).

P.S. - I cannot touch the main. PLEASE HELP, 4 days on the same code.

]
import java.lang.reflect.Array;
import java.util.Arrays;
 
import javax.swing.*;
 
public class Program6
{
    // Modify the constant below to have your name instead of CIS Faculty
    public final static String TITLE_BAR = "Program 6 (Me)";
 
    // Write your class methods below
 
    // Passed the user input string and an array (size = length of the string)
    // for storing the chars of that string. Stores each char of the string to
    // the array.
    private static void storeAllCharacters(String input, char[] allCharacters)
    {
        String strOrig = "";
        allCharacters = strOrig.toCharArray();
    }
 
    private static int storeNoRepeatCharacters(String input,
            char[] noRepeatCharacters)
    {
 
        int stored = noRepeatCharacters.length;
        char[] nonDup;
        nonDup = new char[stored];
 
        for(int i = 0; i <= stored; i++)
        {
            if(input.charAt(i) != input.charAt(stored))                   
            {
                return nonDup[i];
            }
 
        }
        return 0;
 
//        int index = 1;
//        for (int i = 1; i < length; ++i)
//        {
//            int j;
//            for (j = 0; j < index; ++j)
//            {
//                if (noRepeatCharacters[i] == noRepeatCharacters[j])
//                {
//                    break;
//                }
//            }
//            if (j == index)
//            {
//                noRepeatCharacters[index] = noRepeatCharacters[i];
//                ++index;
//            }
//        }
//        for (; index < length; index++)
//        {
//            noRepeatCharacters[index] = 0;
//        }
//        return index;
    }
 
    private static boolean isCharacterPresent(char repeat, char[] noRepeat, int index)
    {
        for(int i = 0; i <= noRepeat.length; i++)
        {
            if(noRepeat[i] == repeat)
            {
                return true;
            }
        }
        return false;
    }
 
    private static void sortArray(char[] noRepeatCharacters, int lastIndexStored)
    {
        Arrays.sort(noRepeatCharacters);
    }
 
    private static void printArray(char[] allCharacters)
    {
        int j = 0;
        char[] temparray = allCharacters;
        boolean isPalindrome = false;
        if (isPalindrome)
        {
            System.out.print(temparray);
 
        }
        for (int i = allCharacters.length - 1; i >= 0; i--)
        {
            temparray[j++] = allCharacters[i];
        }
 
        for (int i = 0; i < allCharacters.length; i++)
        {
            allCharacters[i] = temparray[i];
        }
        System.out.print(temparray);
    }
 
    private static void printArray(char[] noRepeatCharacters,
            int lastIndexStored)
    {
        for(int i = 0; i <= lastIndexStored; i++)
        {
            System.out.print(noRepeatCharacters[i] + " ");
        }
        System.out.print("\n");
        for(int i = noRepeatCharacters.length -1; i <= 0; i++)
        {
            System.out.print(noRepeatCharacters[i]);
        }
        // Start from the size of the array (minus 1 to get the highest subscript)
        // and go down to zero
        for (int i = noRepeatCharacters.length - 1; i >= 0; i--)
        {
            System.out.println(noRepeatCharacters[i]);
        }
 
    }
 
    private static boolean isPalindrome(String input)
    {
        int lowNum = 0;
        int highNum = input.length() - 1;
 
        while (lowNum < highNum)
        {
            if (input.charAt(lowNum) != input.charAt(highNum))
                return false;
 
            lowNum++;
            highNum--;
        }
        return true;
    }
 
    // Main method provided
    // Do not modify the main method
    public static void main(String[] args)
    {
 
        // Local Variables.
        String input = "";
        char[] allCharacters;
        char[] noRepeatCharacters;
        int lastIndexStored;
 
        do
        {
            input = JOptionPane.showInputDialog("Enter a non-empty string");
            if (input == null)
            {
                JOptionPane.showMessageDialog(null,
                        "User clicked cancel. The Program will exit",
                        TITLE_BAR, JOptionPane.PLAIN_MESSAGE);
                System.exit(0);
            }
        } while (input.length() == 0);
 
        // Convert the string to all lower case
        input = input.toLowerCase();
 
        // Create the arrays using the length of the input string
        allCharacters = new char[input.length()];
        noRepeatCharacters = new char[input.length()];
 
        // Call the method to store the entire input string
        storeAllCharacters(input, allCharacters);
 
        // Call the method to print the entire allCharacters array
 
        // Call the method to store the characters without repeating
        // and assign its return value
        lastIndexStored = storeNoRepeatCharacters(input, noRepeatCharacters);
 
        // Call the method to print the noReapeatCharacters array
        // up to the lastIndexStored
        printArray(noRepeatCharacters, lastIndexStored);
 
        // Call the method to sort the noReapeatCharacters array
        // up to the lastIndexStored
        sortArray(noRepeatCharacters, lastIndexStored);
 
        // Call the method to print the sorted noReapeatCharacters array
        // up to the lastIndexStored
        printArray(noRepeatCharacters, lastIndexStored);
 
    } // end of main
 
} // end of Program6

So what part specifically do you need help on?

Hi,
Please just tell i f you are getting any exception or what is your specific issue.
Debug your code by putting some breakpoints and let us know.

Core java

I have worked most of it out. But for some reason the string is converted into an array, but it is not held and printed. I don't know what's going on now.

 
import java.util.Arrays;
import javax.swing.*;
 
public class Program6
{
    // Modify the constant below to have your name instead of CIS Faculty
    public final static String TITLE_BAR = "Program 6 (ME)";
 
    // Write your class methods below
 
    // Passed the user input string and an array (size = length of the string)
    // for storing the chars of that string. Stores each char of the string to
    // the array.
    private static void storeAllCharacters(String input, char[] allCharacters)
    {
        for(int i = 0; i < input.length()-1; i++)
        {      
            allCharacters = input.toCharArray();
            //return;
        }   
    }
 
    private static int storeNoRepeatCharacters(String input,
            char[] noRepeatCharacters)
    {
        int stored = -1;
 
        for (int i = 0; i < input.lastIndexOf(input); i++)
        {
            if (isCharacterPresent(input.charAt(i), noRepeatCharacters, stored))
            {
                noRepeatCharacters[++stored] = input.charAt(i);
            }
        }
        return stored;
    }
 
    private static boolean isCharacterPresent(char repeat, char[] noRepeat,
            int index)
    {
        for (int i = 0; i < index; i++)
        {
            if (noRepeat[i] == repeat)
            {
                return true;
            }
        }
        return false;
    }
 
    private static void sortArray(char[] noRepeatCharacters, int lastIndexStored)
    {
        Arrays.sort(noRepeatCharacters, 0, lastIndexStored + 1);
    }
 
    private static void printArray(char[] allCharacters)
    {
        for (int i = allCharacters.length-1; i >= 0; i--)
        {
        if(!isPalindrome(""))
        {
            JOptionPane.showMessageDialog(null, "User input string is a palindrome " + "\n" + allCharacters[i]);
        }
        else
            JOptionPane.showMessageDialog(null, allCharacters[i], TITLE_BAR, 
                    JOptionPane.PLAIN_MESSAGE);
        }
     }
 
 
    private static void printArray(char[] noRepeatCharacters,
            int lastIndexStored)
    {
        String output = "";
        String output2 = "";
 
        for (int i = 0; i <= noRepeatCharacters.length - 1; i++)
        {
            output += noRepeatCharacters[i];
        }
 
        for (int i = noRepeatCharacters.length - 1; i <= lastIndexStored; i--)
        {
            output2 += noRepeatCharacters[i];
        }
        JOptionPane.showMessageDialog(null, output + "\n" + output2, TITLE_BAR, 
                JOptionPane.PLAIN_MESSAGE); 
    }
 
    private static boolean isPalindrome(String input)
    {
        int lowNum = 0;
        int highNum = input.length() - 1;
 
        while (lowNum < highNum)
        {
            if (input.charAt(lowNum) != input.charAt(highNum))
                return false;
 
            lowNum++;
            highNum--;
        }
        return true;
    }
 
    // Main method provided
    // Do not modify the main method
    public static void main(String[] args)
    {
 
        // Local Variables.
        String input = "";
        char[] allCharacters;
        char[] noRepeatCharacters;
        int lastIndexStored;
 
        do
        {
            input = JOptionPane.showInputDialog("Enter a non-empty string");
            if (input == null)
            {
                JOptionPane.showMessageDialog(null,
                        "User clicked cancel. The Program will exit",
                        TITLE_BAR, JOptionPane.PLAIN_MESSAGE);
                System.exit(0);
            }
        } while (input.length() == 0);
 
        // Convert the string to all lower case
        input = input.toLowerCase();
 
        // Create the arrays using the length of the input string
        allCharacters = new char[input.length()];
        noRepeatCharacters = new char[input.length()];
 
        // Call the method to store the entire input string
        storeAllCharacters(input, allCharacters);
 
        // Call the method to print the entire allCharacters array
        printArray(allCharacters);
 
        // Call the method to store the characters without repeating
        // and assign its return value
        lastIndexStored = storeNoRepeatCharacters(input, noRepeatCharacters);
 
        // Call the method to print the noReapeatCharacters array
        // up to the lastIndexStored
        printArray(noRepeatCharacters, lastIndexStored);
 
        // Call the method to sort the noReapeatCharacters array
        // up to the lastIndexStored
        sortArray(noRepeatCharacters, lastIndexStored);
 
        // Call the method to print the sorted noReapeatCharacters array
        // up to the lastIndexStored
        printArray(noRepeatCharacters, lastIndexStored);
 
    } // end of main
 
} // end of Program6