students file[ctr];
cout<<"Student ID: ";
cin>>file[ctr].studentID;
That is wrong; you are declaring an array of
students
objects, and immediately using the count as an index into the array (valid array indices go from 0 to count - 1). So in this case it means that the structure you create will be overwriting your memory and ultimately cause some random event, such as an application crash. You should do it like:
int count;
students file[count];
int ctr;
for (ctr = 0; ctr < count; ++ctr)
{
cout<<"Student ID: ";
cin>>file[ctr].studentID;
}