# sumDigits challenge

Hi,

http://codingbat.com/prob/p163932

I am working on above challenge
Given a non-negative int n, return the sum of its digits recursively (no loops). Note that mod (%) by 10 yields the rightmost digit (126 % 10 is 6), while divide (/) by 10 removes the rightmost digit (126 / 10 is 12).

sumDigits(126) → 9
sumDigits(49) → 13
sumDigits(12) → 3

i was not sure how to find the sum of digits recursively without loop which i worked earlier. please advise
JavaJava EEProgramming Languages-OtherProgrammingProgramming Theory

Last Comment
rrz

8/22/2022 - Mon
d-glitch

Do you remember how to break up an integer into the LAST digit and the REST using % and / .

Recursion works by letting a function call itself multiple times, each time with a smaller or simpler argument.

The pseudo code would be something like:
``````function sumDigits( n)
sum = 0
if arg = 0
return sum
else
sum = sum + LAST( arg) + sumDigits( REST( arg))
``````

RECURSION is probably the single most important and elegant topic in computer science.
You should really read up on it if you don't understand the concept.  Challenges are not going to be enough.
gudii9

Do you remember how to break up an integer into the LAST digit and the REST using % and / .
yes
RECURSION is probably the single most important and elegant topic in computer science.
You should really read up on it if you don't understand the concept.  Challenges are not going to be enough.
where should i read up on it? Any best material,book, site?
d-glitch

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SOLUTION
rrz

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gudii9

I will try
gudii9

``````public int sumDigits(int n) {
if (n < 10)
{return n;
}
return (n % 10) + sumDigits(n/10);
}
``````

above passes all test. any improvements or alternate approaches?
rrz

if (n < 10)
{return n;
Brilliant! I like your base case much better.