input array of strings

I am trying to get an input of polynomial and put it into an array of strings, but I can't make a condition to exit a loop.
Here is a fragment of my code:
void get(istream& ins)
{
vector <string> a(80);
int N=0, i=0;
string x;
while(cin>>x) // with this condition loop never exits
{
a[N++]=x; }


Thanks for helping.

To do this you'll probably want to set a specific value to be entered to break the loop. So for example if '-1' is read in then the loop should be broken. To do this you may want to read it into a separate variable and test it before putting it in the array if you don't want it to appear there.

Hope this helps,

-KM-

Thanks.