2. An example

• Consider:

  
  #include <iostream>
  
  using namespace std;
  
  int main()
  {
      int num = 0;
      int sum = 0;
      for (;;) {
          cout << "Enter an integer: ";
          cin >> num;
          sum += num;
          cout << "The sum of numbers is " << sum << endl;
      }
      return 0;
  }//main()
  
  

• If non-numeric input is given, the program misbehaves badly.