creating a perfect number function
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Hi. I am currently having a prob. I need to create a function that takes in the number(n) as argument and returns true if n is a perfect number. I am not allowed to use vectors and for loop for this question. I am stuck at this few codes:
function num = perfect(n)
i=1;
sum = 0;
while i <= n/2
if rem(n,i) == 0
else
i = i +1
end
sum = sum + i;
end
if n == sum
n = true
I am a beginner in Matlab and I require assistance. Any kind soul out there to help me? Thanks!
1 Comment
John D'Errico
on 30 Aug 2016
Using the name sum as a variable name will create problems down the road for you. Don't name variables the same as useful functions that you will later need. Or expect to see lots of bugs in your code. Of course, you might like buggy code. Your choice.
Accepted Answer
Guillaume
on 30 Aug 2016
First and foremost, learn to use matlab's debugger. Step through your code, see how the variables change after each instruction, and check that the result was what you expected.
There is clearly a problem with your code. You have a while loop that essentially says:
while i is some value
if some condition
do nothing. Particularly, do not change i
else
change i
end
do something that does not change i
end
You can see that under some condition i never changes, so the loop will repeat infinitely. You need to fix that.
As per John's comment, don't use sum as a variable name, as you won't be able to use the sum function.
Also note that
if somecondition
else
do something
end
is better written as
if ~somecondition
do something
end
2 Comments
Guillaume
on 31 Aug 2016
Yes, that's much better.
One small improvement you can do is get rid of the final if and simply do:
num = n == factorsum;
More Answers (1)
alex usefi
on 10 Sep 2018
How to get numbers like this from the code? is_perfect(6)
show result code: 1 2 3
1 Comment
Guillaume
on 10 Sep 2018
Edited: Guillaume
on 10 Sep 2018
Please start your own question rather than highjacking the answer box of an another question for something that clearly is not an answer.
Note that I would expect that a function called is_perfect to return either true or false, not a vector of numbers.
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