String Palindrome in java: Algorithm and programs

What is a string palindrome in java?

String palindrome in java is the number or the string is the same after reversing it.

for example:-

  1. we take a number 121 the palindrome of this number is 121, so it is a palindrome number.
  2. next, we take number 123 the palindrome of this number is 321, so it is not a palindrome number.
  3. now we take a string “baab” the palindrome of this string is “baab”, so it is a palindrome string.
  4. now we take a string “gettingplaced” the palindrome of this string is “decalpgnitteg”, so it is not a palindrome string.

Algorithm

 

START
Step 1 → Take a sting a
Step 2 → find the lenght of string using length() in n
Step 3 → using for loop (loop=n-1;loop>=0;loop-)
Step 4 → take an integer b
Step 5 → initilized b with b+a.charAt(loop);
Step 6 → if a.equalsIgnoreCase(b) is palindrome
Step 7 → else it is not palindrome
STOP

The string is a palindrome in java using a scanner

 

import java.util.*;
public class Main
{
public static void main(String args[])
{
String x, y = “”;
Scanner s = new Scanner(System.in);
System.out.print(“Enter the string : “);
x = s.nextLine();
int n = x.length();
for(int loop = n – 1; loop >= 0; loop–)
{
y = y + x.charAt(loop);
}
if(x.equalsIgnoreCase(y))
{
System.out.println(“The string is a palindrome”);
}
else
{
System.out.println(“The string is not a palindrome”);
}
}
}

Output

Input – Enter the string: baab Output – The string is a palindrome

The string is a palindrome in java using a while loop

public class palindrome {
    static boolean Palindrome(String st)
    {
        int n = 0, m = str.length() - 1;
        while (n < m) {
            if (str.charAt(n) != str.charAt(m))
                return false;
            n++;
            m--;
        }
        return true;
    }
    public static void main(String[] args)
    {
        String st = "gettingplaced";
 
        if (Palindrome(st))
            System.out.print("Yes,it is palindrome");
        else
            System.out.print("No,it is not palindrome");
    }
}

Output

 

No,it is not palindrome

The string is a palindrome in java using a for loop

 

import java.util.*;

class Palindrome {

public static void main(String args[])

{

String b = “”;

String st = “gettingplaced”;

int n = st.length();

for ( int loop = n – 1; loop >= 0; loop– )

b = b + st.charAt(loop);

if (st.equals(b))

System.out.println(” string is a palindrome.”);

else

System.out.println(” string is not a palindrome.”);

}

}

Output

string is not a palindrome.

 

 

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