# 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.

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