7) Python Program to Display Fibonacci Sequence Using Recursion
Fibonacci sequence:
A Fibonacci sequence is a sequence of integers which first two terms are 0 and 1 and all other terms of the sequence are obtained by adding their preceding two numbers.
For example: 0, 1, 1, 2, 3, 5, 8, 13 and so on...
See this example:
def recur_fibo(n):
if n <= 1:
return n
else:
return(recur_fibo(n-1) + recur_fibo(n-2))
# take input from the user
nterms = int(input("How many terms? "))
# check if the number of terms is valid
if nterms <= 0:
print("Plese enter a positive integer")
else:
print("Fibonacci sequence:")
for i in range(nterms):
print(recur_fibo(i))
8)Python Program to Find Factorial of Number Using Recursion
Factorial:
Factorial of a number specifies a product of all integers from 1 to that number. It is defined by the symbol explanation mark (!).
For example: The factorial of 5 is denoted as 5! = 1*2*3*4*5 = 120.
See this example:
def recur_factorial(n):
if n == 1:
return n
else:
return n*recur_factorial(n-1)
# take input from the user
num = int(input("Enter a number: "))
# check is the number is negative
if num < 0:
print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
print("The factorial of 0 is 1")
else:
print("The factorial of",num,"is",recur_factorial(num))