1. Please use Java to code the program, thank you!
Write a program that asks the user to enter a sentence. The program then passes the String into a
method called convertString that changes the String to an array of chars and returns the array.
The program then passes the array into a method called isReverse and returns true/false if the
array of chars is a palindrome. Ignore whitespace and punctuation (space, tab, single quote,
double quote, exclamation, comma, question mark, hyphen, semi-colon, colon, period). Ignore
case as well. For example, all these inputs are palindromes: A man, a plan, a canal, panama. Was
it a car or a cat I saw?"If I had a hi-fi!!" Use the following template: import java.util.Scanner;
Solution
Given below is the code for the question with output. Hope it helps. If it did, please do rate the
answer . Thank you very much
import java.util.Scanner;
public class Ex1 {
public static void main(String[] args) {
Scanner keybd = new Scanner(System.in);
System.out.println("Enter a sentence: ");
String sentence = keybd.nextLine();
char[] arr = convertString(sentence);
if(isReverse(arr))
System.out.println(sentence + " is a palindrome");
else
System.out.println(sentence + " is NOT a palindrome");
}
//convert the input string into lower case and returns the array
public static char[] convertString(String s)
{
char[] arr = new char[s.length()];
for(int i = 0; i < s.length(); i++)
{
char ch = s.charAt(i);

2. if(ch >= 'a' && ch <= 'z') //lower case .. no change
arr[i] = ch;
else if(ch >= 'A' && ch <= 'Z') //is it upper case ? change to lower
arr[i] = (char) (ch - 'A' + 'a');
else //other characters no change
arr[i] = ch;
}
return arr;
}
//input is array of lower case letters and other special characters
public static boolean isReverse(char[] arr)
{
int i = 0;
int len = arr.length;
int j = arr.length - 1;
char ch1, ch2;
while(i < len && j >= 0)
{
//skip from left to right any non alphbetci characters, get the 1st letter from left
//to be matched.
do
{
ch1 = arr[i++];
}while(i < len && (ch1 < 'a' || ch1 > 'z'));
//skip from right to left any non alphabetic characters, get the 1st letter from left
//to be matched.s
do
{
ch2 = arr[j--];
}while(j >= 0 && (ch2 < 'a' || ch2 > 'z'));
if(ch1 != ch2)
return false;
}
return true;
}
}
output
Enter a sentence:
was it a car
was it a car is NOT a palindrome
Enter a sentence:

3. Was it a car OR A CAT I SAW??
Was it a car OR A CAT I SAW?? is a palindrome