How to use if statement in function?

How do I define that my N needs to be >0. I tried if but I get error like

Output argument "prvi" (and maybe others) not assigned during call to "func1".

here is my writen code

function prvi = func1(x, N)

for k=1:N

prvi=(1-(4*x^2)/(pi^2*(2*k-1)^2))

end

end

Answer 1

[James Tursa]

Add this code to the top of your function:

if( N <= 0 )
    error('N needs to be > 0')
end

That being said, your loop probably doesn't do what you intended since it only assigns prvi based on the last iteration. Also, there are many other checks you can make on x and N to make sure they are the correct type, size, etc.

[Cris LaPierre]

You could also look into Function Argument Validation.

[Roko Serdar]

thank you guys