How to define array length based on input

[Icenel]

I have problem with array
Input prime number, then input is n
example input : 29
length array is n-1
then define array should be int primeNumber[n-1];

add to that array with prime number 2 until 29
then array will be
primeNumber[28] = {2,3,5,7,11,13,17,19,23,29}

And the last is print array
output is "Prime number is 2 3 5 7 11 19 23 29."
"number of prime number is 8"

Please help me Thank you

[kbw]

http://www.cplusplus.com/forum/beginner/8473/#msg39179