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How to check if a string is a palindrome in Kotlin

How to check if a string is a palindrome in Kotlin.

Here is a step-by-step tutorial on how to check if a string is a palindrome in Kotlin:

Step 1: Get the input string​

First, you need to get the input string from the user. You can do this by using the readLine() function, which reads a line of text from the standard input. Here's an example:

val input = readLine()

Step 2: Remove whitespace and convert to lowercase​

To check if a string is a palindrome, you usually ignore whitespace and consider uppercase and lowercase letters as equal. So, you need to remove any whitespace from the string and convert it to lowercase. You can use the replace() function to remove whitespace, and the toLowerCase() function to convert the string to lowercase. Here's an example:

val cleanedInput = input?.replace("\\s".toRegex(), "")?.toLowerCase()

Step 3: Create a reversed version of the input string​

To check if a string is a palindrome, you need to compare it with its reverse. You can create a reversed version of the input string using the reversed() function. Here's an example:

val reversedInput = cleanedInput?.reversed()

Step 4: Compare the input string with its reverse​

Finally, you can compare the input string with its reverse to check if it is a palindrome. You can use the equals() function to compare the two strings. If they are equal, then the input string is a palindrome. Here's an example:

val isPalindrome = cleanedInput?.equals(reversedInput)

Step 5: Print the result​

To inform the user whether the input string is a palindrome or not, you can print the result. You can use an if-else statement to determine the output message. Here's an example:

if (isPalindrome == true) {
    println("The input string is a palindrome.")
} else {
    println("The input string is not a palindrome.")
}

That's it! You have successfully checked if a string is a palindrome in Kotlin. Here's the complete code:

fun main() {
    val input = readLine()
    val cleanedInput = input?.replace("\\s".toRegex(), "")?.toLowerCase()
    val reversedInput = cleanedInput?.reversed()
    val isPalindrome = cleanedInput?.equals(reversedInput)

    if (isPalindrome == true) {
        println("The input string is a palindrome.")
    } else {
        println("The input string is not a palindrome.")
    }
}

You can run this code and test it with different input strings to see if they are palindromes or not.