Write a recursive function to print first N even number using Python

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im absolute beginner in programming world.python is my first programming language ..i solved it without recursion but how can i code it using recursion its become difficult for me

What I have tried:

i tried witout recursion and i solved it

Posted 17-Dec-18 7:47am

Member 14092758

Updated 4-Aug-20 6:41am

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Patrice T 17-Dec-18 14:11pm

You should show what you have done so far.
Just show that you have done something :)

2 solutions

Solution 1

First learn what recursion is. You can go that by learning what recursion is.

Recursion is like a loop, but it's different.
If you think about classic exam,ples of recursion, there is factorial:

N! = N * (N - 1)! while N > 1

That's obviously recursive, because the definition of a factorial value is expressed in terms of a factorial of a lesser value (until you run out of values)

So the first big step in implementing a recursive function in any language to to express the operation in terms of a recursive algorithm. I.e. express "N even numbers" as recursive pseudo code. Then you can start implementing it.

Give it a try: this isn't complicated, but it's something you need to get your head around for yourself - being given a solution doesn't teach you anything about how to do it next time!

Posted 17-Dec-18 8:15am

OriginalGriff

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CPallini · Accepted Answer · 2018-12-17T22:04:00

You know, a recursive function calls itself until a stop condition is met. so, in your case you need a function that:

Checks the stop condition (all numbers printed out) and returns if it is met.
Prints the current number.
Calls itself with an incremented argument in order to print the next number.

Something similar to (pseudocode)

even(n, N)
  if n == N then return // stops the recursive process
  print(2*n)
  even(n+1, N) // recursive call

Then you may call it this way

even(0,5)