lab6.py

#    8.12 LAB: Output a linked list
#   
#   Write a recursive function called print_list() that outputs the integer value of each node in a linked list. Function print_list() has one parameter, the head node of a list. The main program reads the size of the linked list, followed by the values in the list. Assume the linked list has at least 1 node.
#   
#   Ex: If the input of the program is:
#   
#   5
#   1
#   2
#   3
#   4
#   5
#   
#   the output of the print_list() function is:
#   
#   1, 2, 3, 4, 5,
#   
#   Hint: Output the value of the current node, then call the print_list() function repeatedly until the end of the list is reached. Refer to the Node class to explore any available instance methods that can be used for implementing the print_list() function.

class Node:
    def __init__(self, value):
        self.data_val = value
        self.next_node = None

    def insert_after(self, node):
        tmp_node = self.next_node
        self.next_node = node
        node.next_node = tmp_node

    def get_next(self):
        return self.next_node

    def print_data(self):
        print(self.data_val, end=", ")

# Solution:
def print_list(head_node, current_node=None):
    
    # initial setup for current node on first call
    if current_node == None:
        current_node = head_node
        
    # base case, if we're out of nodes
    if (current_node.get_next() == None):
        current_node.print_data()
            
    # recursive case
    else:
        current_node.print_data()
        print_list(head_node, current_node.get_next())
# End Solution

if __name__ == "__main__":
    size = int(input())
    value = int(input())
    head_node = Node(value) # Make head node as the first node
    last_node = head_node
    
    # Insert the second and the rest of the nodes
    for n in range(1, size):
        value = int(input())
        new_node = Node(value)
        last_node.insert_after(new_node)
        last_node = new_node
    
    print_list(head_node)