Side Effects Illustrated
void CountChars();
int count = 0;    // Supposed to count input lines
char ch;          // Hold one input character
int main()
{
   cin.get(ch);
   while(cin)
   {
      count++;
      CountChars();
      cin.get(ch);
   }
   cout << count << “ lines of input processed.” << endl;
   return 0;
}