I need help

Question

Example 1.

def fun(x):
if x == 0:
return 0
return x + fun(x-1)
print(fun(3))

Output: 6

Example 2.

def apply_twice(func, arg):
return func(func(arg))

def add_five(x):
return x + 5

print(apply_twice(add_five, 10))

Output: 20

I need to ask why not function value add in x in 1 example
while in 2 examples function values save then it will be argument of another function.

Please guide me....

Answer 1

https://www.sololearn.com/discuss/1914313/?ref=app

Answer 2

The recursive function in example 1 works correctly. The calculation performed is 3+2+1+0 = 6.

The calculation in example 2 ist also correct: (10+5)+5 = 20.

Answer 3

Michael i understand how the answer is ganerted
but i need to ask
=> return x + fun(x-1)
=> return 3 + fun(2)
why not add value of fun in x
=> return 3 + Value of fun(2)

Answer 4

You can see code running step by step on http://pythontutor.com/visualize.html
And mutable of variables also you can see
For my learning it's big help