How to Use the Fibonacci Function

Enter a number in the input box below to test the function.

This function calculates the nth Fibonacci number.

To use the function, simply input the desired number into the 'n' parameter.

Common mistakes include:

• Inputting a negative number
• Inputting a non-integer

Click here to toggle the function code.

def fib(n):
    if n<=0:
        print("Incorrect input")
    elif n==1:
        return 0
    elif n==2:
        return 1
    else:
        a = 0
        b = 1
        c = 1
        for i in range(n - 2):
            c = a + b
            a = b
            b = c
        return c