def convert(num): if num == 0: return 0 else: return (num % 2 + 10 * convert(num // 2))

Question

It's recursion example in the lesson but i am unable to understand how it's working please help me

Answer 1

Alright let's analyse this code together
def convert(num): #here we create a function named convert which takes interger values represented by num in the bracket

if num == 0: #this is the base case which means when the function is called the last value to be processed by the function will be will be 0
return 0
else:
return (num % 2 + 10 * convert(num // 2)) #for the last step you'll better understand with an example

If below the line we implemented
print (convert(3))

As 3 is not equal to 0
The function will process the else statement:
(3 % 2 + 10 * convert(3//2)) which is equal to (1 +10 * convert(1))

Now let's process convert(1)
As 1 is not 0 the else statement is done :
(1 % 2 + 10 * convert(1//2)) which is equal to (1 + 10 * convert(0))

Now we substitute the value of convert(1) in convert (3) and we get
(1+ 10 * (1 + 10 *convert(0)))

And lastly it's time for convert(0) to be processed
As 0 is equal to 0 the recursion is ended
Output: (1 + 10*(1 + 10 * 0)) = 11

Answer 2

https://www.geeksforgeeks.org/JUMP_LINK__&&__python__&&__JUMP_LINK-return-statement/amp/

Answer 3

The purpose of this code is to convert from denary numbers to binary numbers

Answer 4

[En]moVes well that's right, but I don't get the part where you're saying that he has an error in the code, I don't think he has any

Answer 5

Take a look at the output of this code, I hope it helps you understand how the recursive function works. Good luck!
☺️

def convert(num):
if num == 0:
return 0
arg = num//2
print(num,'// 2 =',arg)
rec = convert(arg)
out = num % 2 + 10 * rec
print(num,'% 2 + 10 *',rec,'=',out)
return out

print(convert(20))

Answer 6

You called this recursion, and with each function call, the value decreases so that there is no infinite loop...

Answer 7

Zen Ai I'm sorry, it seemed to me that Enter is where the function call is

Answer 8

mohsin raza this is what is done but that's a general formula used for it when using recursion , there's another way to do so that doesn't use it, well I'm sure with continuous learning you'll get it in the end

Answer 9

Ok

Answer 10

mohsin raza
you can expand the recursive function to:

print(convert(5))

print((5%2+10*(2%2+10*(1%2+10*0))))

Answer 11

Thanks Zen Ai but i am still confused with algorithm of conversion decimal to binary

Answer 12

I have learned decimal to binary conversion is simply divide by 2 and note remainder

Answer 13

In a simple way. Recursion is a function that calls itself. And you have an error, the function convert call should be in else