"Java

The following class is given:

import java.util.Arrays;

public class StringImproved $\{$

$/**$

$*$ Field Detail

$*$ The storage for the characters in the StringImproved class

$*/$

private char$[]$ charArray;

$//$Initialize storage string

public StringImproved$($int size$)\{$

if$($size $<1)\{$

System.out.println$(""$Size should be a positive number""$)$;

$\}$

charArray $=$ new char$[$size$]$;

$\}$

public static void main$($String$[]$ args$)\{$

$//$ TODO Auto$-$generated method stub

StringImproved stringImproved $=$ new StringImproved$(5)$;

System.out.println$($stringImproved$.$append$(""$abcde$""))$;

System.out.println$($stringImproved$)$;

$\}$

$\}$

Write the following methods for the class:

$1)$ lastIndexOf

public int lastIndexOf$($char ch$)$

Find the last instance of the character in the StringBuffer.

Difficulty $3/10$

Parameters:

ch $-$ The character to search for.

Returns:

The index of the last instance of the nominated character, $-1$ otherwise.

$2)$ length

public int length$()$Returns the length of the string. The length of the string is t XU$06$ he number of characters, digits, and punctuation, including space,

in the string. For example, $""$Hello$""$ has a length of $5,$ and $""$Hello world."" is length $12.$

Difficulty: $1/10$

Returns:

The length of the string. $-1$ in the event of an error.

$3)$ prepend

public boolean prepend$($java$.$lang.String newString$)$

Prepend the nominated string to the StringImproved object.

Difficulty $1/10($if you are clever$)$

Parameters:

newString $-$ The string to append.

Returns:

true if successful, false otherwise."