A function to find prime number

Hello,

I wrote a function to find a prime number and would like to run it to find all prime numbers up to 100 from my starting point. However, I get an error saying "too many output arguments".

Here is what I have...

function isPrime(number)
tf=isprime(number);
if tf==true
    disp(number)
end
end

starting_point=input("Enter your number: ");
while starting_point<100
    disp(isPrime(starting_point))
    starting_point=starting_point+1;
end

I would really appreciate if anyone can help me with this problem....

Answer 1

[James Tursa]

Your function doesn't return anything, so when you try to use its output you get an error. Change this:

function isPrime(number)

to this

function tf = isPrime(number)

[Takashi Fukushima]

Thank you so much for your advice.

Based on your advice, I fixed it like this...

function [result]=isPrime(number)

tf=isprime(number);

if tf==true

result=number;

else

result=0;

end

end

number=input("Enter your number: ");

while number<100

result=isPrime(number)

number=number+1;

end

However, the problem here is that output shows "result=0" which I don't want it to show. I am not sure how I can surpress the appearance.

[James Tursa]

Put a semi-colon at the end of the assignment line to suppress the output:

result=isPrime(number);

[Takashi Fukushima]

Thank you so much! I made it!

Answer 2

[John D'Errico]

Hey, you wrote some code! Credit for that. :-)

But what did you do?

function isPrime(number)
tf=isprime(number);
if tf==true
    disp(number)
end
end

This function has NO outputs! None at all. It dumps somethign to the command window, but that is all. It does NOT return a result.

But then, how do you use it?

disp(isPrime(starting_point))

you use it, expecting an output.

What was the error message?

"too many output arguments"

So you wrote a function that returns no arguments, but then you used it expecting an output argument. Therein lies the problem. The fact is however, you are not using any output from isPrime, and it already dumps a comment to the command window.

Just change the code you use to this:

starting_point=input("Enter your number: ");
while starting_point<100
    isPrime(starting_point)
    starting_point=starting_point+1;
end

[Takashi Fukushima]

Thank you so much for your answer.

I think that it's the simplest and the most beautiful code for this problem.

Also, I made some progress which you can see above on James's comment although I still have a problem there...