Answer
code
Work Step by Step
# 15.7 (Fibonacci series) Modify Listing 15.2 so that the program finds the number of
# times the fib function is called. (Hint: Use a global variable and increment it
# every time the function is called.)
counter = 0
def fib(index):
global counter
counter += 1
if index == 0: # Base case
return 0
elif index == 1: # Base case
return 1
else: # Reduction and recursive calls
return fib(index - 1) + fib(index - 2)
index = eval(input("Enter an index for a Fibonacci number: "))
fib(index)
print("The Fibonacci function is called", counter, "times")
