how to check?

From: nick (ucheng4_at_csc.cuhk.edu.hk)
Date: 02/28/05 

Date: Mon, 28 Feb 2005 19:39:15 +0800

int main(){
  int x[2];
  x[0]=1;

  printf("%d\n",x[0]);
  printf("%d\n", isspace();

}

x[0] assigned 1
if x[1] is not assigned a value,what will the value contain in x[1]?
how do i know that x[1] is not assigned value?

thanks!