Kotlin Palindrome Number 303

A small, modern Kotlin/JVM console project that prints palindrome numbers in the 100..200 range.

A palindrome number reads the same from left to right and right to left. Examples: 121, 1221, and 12321.

What is included

• Kotlin/JVM project configured with Gradle Kotlin DSL.
• Numeric palindrome detection without converting numbers to strings.
• Reusable isPalindromeNumber and palindromeNumbersIn functions.
• Unit tests for positive, negative, and range-based cases.
• Gradle Wrapper updated to Gradle 9.6.0.

Requirements

• JDK 17 or newer. Kotlin compiles to JVM 17 bytecode.
• No local Gradle installation is required; use the included Gradle Wrapper.

Run

./gradlew run

Expected output:

101 is a palindrome number
111 is a palindrome number
121 is a palindrome number
131 is a palindrome number
141 is a palindrome number
151 is a palindrome number
161 is a palindrome number
171 is a palindrome number
181 is a palindrome number
191 is a palindrome number

Test

./gradlew test

Core implementation

fun isPalindromeNumber(number: Int): Boolean {
    if (number < 0) return false

    var remaining = number
    var reversed = 0

    while (remaining > 0) {
        reversed = reversed * 10 + remaining % 10
        remaining /= 10
    }

    return number == reversed
}

License

This project is licensed under the MIT License. See LICENSE.