Kotlin program: Calculate the factorial of a given number

Kotlin Basic: Exercise-8 with Solution

Write a Kotlin program to find the factorial of a given number.

Sample Solution:

Kotlin Code:

fun main() {
    val number = 5
    val factorial = calculateFactorial(number)
    println("Factorial of $number: $factorial")
 }

fun calculateFactorial(number: Int): Long {
    return if (number == 0 || number == 1) {
        1
    } else {
        var result = 1L
        for (i in 2..number) {
            result *= i
        }
        result
    }
}

Sample Output:

Factorial of 5: 120

Explanation:

In the above exercise,

• Inside the "main()" function, a variable named 'number' is declared and assigned a value of 5.
• The calculateFactorial() function is then called with the number as an argument, and the result is stored in a variable named factorial.
• Finally, the result is printed using string interpolation in the println() statement: "Factorial of $number: $factorial".

In the calculateFactorial() function,

• The function takes an integer number as a parameter and returns the factorial as a Long value.
• Inside the function, an if statement checks if the number is equal to 0 or 1. If it is, the function returns 1 because the factorial of 0 and 1 is 1.
• If the number is greater than 1, the function initializes a variable result with 1L, indicating the starting value for the factorial calculation.
• A for loop is used, starting from 2 (as the factorial calculation starts from 2) and continuing until number. In each iteration, the result is multiplied by i and assigned back to the result.
• Finally, the calculated factorial is returned.

Kotlin Editor:

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