# Kotlin Tail-Recursive function: Calculate the power of a number

## Kotlin Function: Exercise-17 with Solution

Write a Kotlin tail-recursive function to calculate the power of a number.

**Sample Solution:**

**Kotlin Code:**

```
tailrec fun power(base: Int, exponent: Int, result: Int = 1): Int {
if (exponent == 0) {
return result
}
return power(base, exponent - 1, result * base)
}
fun main() {
val base = 3
val exponent = 5
val result = power(base, exponent)
println("$base raised to the power of $exponent is: $result")
}
```

Sample Output:

3 raised to the power of 5 is: 243

**Explanation:**

In the above exercise -

- The "fibonacci()" function takes three parameters: n, which represents the position of the Fibonacci number to be calculated, a and b which are used to keep track of the previous two Fibonacci numbers.
- If n becomes 0, we have reached the desired position and return a, the current Fibonacci number.
- In each recursive call, we decrement n by 1 and calculate the next Fibonacci number by adding the previous two Fibonacci numbers (a + b). The current value of b becomes the new value of a, and the sum a + b becomes the new value of b.
- By using tail recursion, we make the recursive call directly without any additional computation.
- The recursive calls continue until the base case is reached and the final Fibonacci number is computed.

**Kotlin Editor: **

**Previous:** Calculate the nth Fibonacci.

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