Prime number or its nearest prime numbers

anyone please tell me in matlab how to write a function to find prime number of any number if it is not prime number then function show its nearest prime numbers... let take example ...take number 9 we know it is not prime then the program will show its nearest prime like 7 and 11..

[Thomas]

if this is homework, can you show, what you have done so far?

[Jan]

What have you tried so far and which problem occurred?

Answer 1

[Andrei Bobrov]

input x

x = 24;

solution

X = [x x];
out = zeros(1,2);
while 1
   t = isprime(X);
   if all(t)
       out = X;
       break
   elseif any(t)
       out(t) = X(t);
       t1 = ~t;
       X(t1) = X(t1) - sum([1 -1].*t1);
   else
       X = X - [1 -1];
   end
end
out = unique(X)

[Jan]

I assume, this is the solution of Rahul's homework, Andrei.

[Rahul Singh]

thanks Andrei Bobrov........i think this is useful answer for me............

Answer 2

[Sean de Wolski]

isprime() will be your friend.