PART I:
  Write a C++ program to input a Fahrenheit temp
    from the user.

  Convert it to Celsius and print it out.

         5
    C = --- ( F - 32 )         // Watch out for
         9                     // integer division!

 PART II:
  If the temp is boiling (C above 100), print
    a message.
  If the temp is freezing (C below 0), print
    a message.

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 NOTES:
  A VARIABLE is an object with a name.
  An OBJECT is assigned memory and has a TYPE.
  A TYPE defines structure and operations.

   e.g. int x = 5;
       // operations:  +  -  *  /  %  etc.

---------------------------------------------------

  void
  do_something( double a[], int n )
  {
    // 
    for ( int i = 0 ; i < n ; i++ )
    {
      if ( a[i] < 0 )
        a[i] = 0;
    }
  }

  int main()
  {
    double b[100];

    // ... read in values for b

      // the value of b is the mem location
      //   of the array, which is passed by value
    do_something( b, 100 );
  }