Question

python 3

We would like to add cursor-based APIs to the array-backed list API. To this end, we are including a cursor attribute, and two related methods. cursor_set will set the cursor to its argument index, and cursor_insert will insert its argument value into the list at the current cursor position and advance the cursor by 1.

E.g, given an array-backed list l that contains the values [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], running the following code

  l.cursor_set(5)
  l.cursor_insert('a')
  l.cursor_insert('b')
  l.cursor_insert('c')

will result in the updated list [0, 1, 2, 3, 4, 'a', 'b', 'c', 5, 6, 7, 8, 9]

When the cursor is set to the length of the list, cursor_insert should behave like append.

Programming rules:

• You should only add code to the cursor_insert method; the rest of ArrayList is provided for reference and testing purposes only. cursor_set is already provided.
• You must adhere to the same rules when using the built-in Python list as you did in the ArrayList lab.
• Assume that cursor is set to a value between 0 and the length of the list (inclusive) when cursor_insert is called.
• You may not use any other data structures (this includes the built-in Python list).

class ArrayList:
def __init__(self):
self.data = []
self.cursor = 0
  
def append(self, val):
self.data.append(None)
self.data[len(self.data)-1] = val
  
def cursor_set(self, idx):
self.cursor = idx
  
def cursor_insert(self, val):
# YOUR CODE HERE

Answer 1

Program:

Output:

Summary:

Method cursor_insert(self,val) accepts one paramater val . The val should be inserted into the current position of the curser_set.

If the cursor is the length of the Arraylist i.e, at the last element then:

Function acts as append

Else using insert(index,element) method it inserts the val into the cursor point.