SubArray Processing

• For many problems we know the maximum capacity
• But not the number of elements in an array.
  • Frequently problems involve a statement like "There will be no more that 200 records"
  • Or you can put a bound on maximum size somehow.
  • This is probably an academic exercise.
• In this case, you will need to store both
  • The capacity or the maximum size of the array (a constant)
  • The size or number of elements in the array (a variable)
• These will need to be passed to all functions that manipulate the array.
• Generally size is
  • The number of actual elements in the array.
  • Initially 0.
  • It is also the next position in the array where something can be inserted.
• This means that the data is normally kept in the first 0..size-1 elements of the array.
• Inserting an element
  • Usually at position size.
• Deleting an element
  • Just move the element to be deleted to the end
  • Fill in the hole created
  • And decrement size.
  • There is no "erase" an element, the memory is still allocated in the array.
• Wrapping the array and the size in a struct is convenient.
• Just remember to pass the struct by const reference instead of by value.
• Write a program to count the number of unique words in a file.