Kotlin Class: MathUtils class with static functions

Last update on August 27 2025 12:39:39 (UTC/GMT +8 hours)

Write a Kotlin program that creates a class 'MathUtils' with static functions to calculate the factorial, square root, and cube root of a number.

Pre-Knowledge (Before You Start!)

Before attempting this exercise, you should be familiar with the following concepts:

Companion Objects: In Kotlin, companion objects allow defining functions that behave like static methods in Java.
Factorial Calculation: The factorial of a number (n!) is calculated as the product of all positive integers from 1 to n.
Math Functions: Using built-in functions like Math.sqrt() and Math.cbrt() to calculate the square root and cube root of a number.
Loops in Kotlin: The for loop is used to compute the factorial by multiplying numbers in a range.
Function Calls: Understanding how to call functions within the main() function and pass arguments.

Hints (Try Before Looking at the Solution!)

Try to solve the problem using these hints:

Hint 1: Define a class named MathUtils and use a companion object to create a static function for factorial calculation.
Hint 2: Implement a loop inside the factorial() function to compute the factorial of a given integer.
Hint 3: Define separate functions for square root and cube root calculations using built-in math functions.
Hint 4: In the main() function, create a variable for the input number and call the three functions to compute and print their results.

Sample Solution:

Kotlin Code:

class MathUtils {
    companion object {
        fun factorial(n: Int): Long {
            if (n == 0 || n == 1) {
                return 1
            }
            var result = 1L
            for (i in 2..n) {
                result *= i
            }
            return result
        }
    }
}

fun sqrt(n: Double): Double {
    return Math.sqrt(n)
}

fun cbrt(n: Double): Double {
    return Math.cbrt(n)
}

fun main() {
    val number = 7

    val factorial = MathUtils.factorial(number)
    println("Factorial of $number is: $factorial")

    val squareRoot = sqrt(number.toDouble())
    println("Square root of $number is: $squareRoot")

    val cubeRoot = cbrt(number.toDouble())
    println("Cube root of $number is: $cubeRoot")
}

Sample Output:

Factorial of 7 is: 5040
Square root of 7 is: 2.6457513110645907
Cube root of 7 is: 1.9129311827723892

Explanation:

In the above exercise -

First we define a class "MathUtils" and declare a "companion" object inside it. The companion object contains static functions. Inside the companion object, we define a function "factorial()" to calculate the factorial of a number using an iterative approach.
We also define top-level functions "sqrt()" and "cbrt()" outside the "MathUtils" class. These functions use the Math.sqrt and Math.cbrt functions from the standard library to calculate the square root and cube root of a number, respectively.
In the "main()" function, we calculate the factorial of a number using the MathUtils.factorial function. We also calculate the square root and cube root using the sqrt and cbrt top-level functions, respectively.

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