Please explain this code with the process that is taking place here

Question

I want to understand logically what is really happening there. I went through other questions in here but don't understand them in clarity.

Explain with this

def fib(num):
if num==1 or num==0:
return 1
else:
return fib(num-2)+fib(num-1)

Answer 1

Edited 3 to 5: Vuyisile Lucas Ncipha
For ex: n=5.
fib(5)
=>fib(5-2) +fib(5-1)= fib(3)+fib(4)

=>[ fib(3-2) + fib(3-1) ] +[ fib(4-2)+fib(4-1) ]

= >[ fib(1) + fib(2)] +[fib(2) +fib(3)]

=>1 + fib(2-2)+ fib(2-1) +fib(2-2)+fib(2-1) +[ fib(1) + fib(2)]

=>1+fib(0)+fib(1)+ fib(0)+fib(1) + [ 1 + fib(2-2)+ fib(2-1)]

=>1+1+1+1+1+ [ 1+ fib(0)+ fib(1)]

=>5+[ 1+1+1]

=> 5+3 = 8.

Answer 2

Def instruction.

A function in python is an object that takes arguments and returns a value. The function is usually defined using the def statement.

In your example is a function "fib" that takes the argument "num"

if num is 1 or 0, the function returns a value 1

if otherwise, then returns value (num-2)+(num-1)

Answer 3

I am trying how did the it give 8 for fib(5). I want to know the step by process for it to reach 8