queues back front front back count the queue now contains seven items in elements [ with one empty slot what happens if value is addedsince we are using circular arraythe same procedure is used and the new item will be inserted into the position immediately following the back marker in this casethat position will be element thusthe queue wraps around the circular array as items are added and removedwhich eliminates the need to shift items the resulting queue is shown hereback front front back count this also represents full queue since all slots in the array are filled no additional items can be added until existing items have been removed this is change from the original definition of the queue adt and requires an additional operation to test for full queue queue implementation given the description of circular array and its use in implementing queuewe turn our attention to the implementation details python implementation of the queue adt using circular array is provided in listing the constructor creates an object containing four data fieldsincluding the counter to keep track of the number of items in the queuethe two markersand the array itself sample instance of the class is illustrated in figure for the circular queuethe array is created with maxsize elements as specified by the argument to the constructor the two markers are initialized so the first item will be stored in element this is achieved by setting front to and back to the index of the last element in the array when the first item is addedback count front back qarray queue (array figure queue object implemented as circular array