COEN79 Lab 3 Solved

Sequence
 

A sequence class is similar to a bag—both contain a bunch of items, but unlike a bag, the items in a sequence are arranged in an order. In contrast to the bag class, the member functions of a sequence will allow a program to step through the sequence one item at a time. Member functions also permit a program to control precisely where items are inserted and removed within the sequence.  

Our sequence is a class that depends on an underlying value_type, and the class also provides a size_type.  

 

Three member functions work together to enforce the in-order retrieval rule:

 

void start( ); 

value_type current( ) const; void advance( ); 

 

§  After activating start, the current function returns the first item  

§  Each time we call advance, the current function changes so that it returns the next item in the sequence  

 

 

Provide some additional useful member functions, such as:

1.    insert_front: insert a new value at the front of the sequence. This new item should now be the current item.

2.    remove_front: remove the value at the front of the sequence. The new front item should now be the current item.

3.    attach_back: insert a new value at the back of the sequence. This new item should now be the current item.

4.    end: The last item in the sequence should now be the current item.

5.    operator+ and operator+=:  These operators should have the precondition that the sum of the sizes of the two sequences being added is smaller than the CAPACITY of a sequence.

 

 

Subscript operator: 

For a sequence x, we would like to be able to refer to the individual items using the usual C++ notation for arrays. For example, if x has three items, then we want to be able to write x[0], x[1], and x[2] to access these three items. This use of the square brackets is called the subscript operator. The subscript operator may be overloaded as a member function, with the prototype shown here as part of the sequence class:  

 

COEN 79L - Object-Oriented Programming and Advanced Data Structures  Lab 3 
 

 

class sequence { public: 

... value_type operator [] (size_type index) const; ... 

 

 

As you can see, the operator[] is a member function with one parameter. The parameter is the index of the item that we want to retrieve. The implementation of this member function should check that the index is a valid index (i.e., index is less than the sequence size), and then return the specified item.

 

For this project, specify, design, and implement this new subscript operator for the sequence.

 

More information about the sequence class is available in Slide Set 3.

 

à The documentation of the sequence class has been provided for you in the sequence1.h file. 

 

• Make sure you include the invariants of the class on top of the implementation 

(*.cpp) file.