# Kotlin – Fibonacci Series using For loop

## Fibonacci series using For loop in Kotlin

In this tutorial, we will learn how to generate the Fibonacci series using a For loop in Kotlin.

## Examples

The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones, usually starting with 0 and 1.

### Generating Fibonacci series

In this example, we will create a function that generates the Fibonacci series up to a given number of terms.

Kotlin Program

``````fun generateFibonacciSeries(terms: Int): List<Int> {
val fibonacciSeries = mutableListOf(0, 1)
for (i in 2 until terms) {
val nextTerm = fibonacciSeries[i - 1] + fibonacciSeries[i - 2]
}
return fibonacciSeries
}

fun main() {
val numberOfTerms = 10
val fibonacciSeries = generateFibonacciSeries(numberOfTerms)
println("Fibonacci Series:")
for (term in fibonacciSeries) {
print("\$term ")
}
}``````

Output

``````Fibonacci Series:
0 1 1 2 3 5 8 13 21 34 ``````

The function `generateFibonacciSeries` takes an integer `terms` as input and returns a list containing the first `terms` Fibonacci numbers. The for loop iterates from 2 to `terms`, calculating each Fibonacci number and adding it to the list.

### Generating Fibonacci series up to a specific number

In this example, we will create a function that generates the Fibonacci series up to a specific number.

Kotlin Program

``````fun generateFibonacciSeriesUpToNumber(number: Int): List<Int> {
val fibonacciSeries = mutableListOf(0, 1)
for (i in 2 until number) {
val nextTerm = fibonacciSeries[i - 1] + fibonacciSeries[i - 2]
if (nextTerm <= number) {
} else {
break
}
}
return fibonacciSeries
}

fun main() {
val number = 50
val fibonacciSeries = generateFibonacciSeriesUpToNumber(number)
println("Fibonacci Series up to \$number:")
for (term in fibonacciSeries) {
print("\$term ")
}
}``````

Output

``````Fibonacci Series up to 50:
0 1 1 2 3 5 8 13 21 34 ``````

The function `generateFibonacciSeriesUpToNumber` takes an integer `number` as input and returns a list containing the Fibonacci numbers up to and including `number`. The For loop iterates from 2 to `number` (exclusive), calculating each Fibonacci number and adding it to the list until the next number exceeds the given `number`. If the next term exceeds the given `number`, the loop is terminated using the `break` statement.

## Summary

In this Kotlin tutorial, we learned how to generate the Fibonacci series using a For loop in Kotlin. We saw two examples: one to generate the series up to a given number of terms and another to generate the series up to a specific number.