This is a Python program to search for an element in a linked list without using recursion.
The program prompts the user for a key to search in a linked list and displays its index.
1. Create a class Node.
2. Create a class LinkedList.
3. Define methods append and display inside the class LinkedList to append data and display the linked list respectively.
4. Define method find_index to search for the key.
5. find_index uses a loop to iterate over the nodes of the linked list to search for the key.
6. Create an instance of LinkedList, append data to it and display the list.
7. Prompt the user for a key to search and search for it.
Here is the source code of a Python program to search for an element in a linked list without using recursion. The program output is shown below.
class Node: def __init__(self, data): self.data = data self.next = None class LinkedList: def __init__(self): self.head = None self.last_node = None def append(self, data): if self.last_node is None: self.head = Node(data) self.last_node = self.head else: self.last_node.next = Node(data) self.last_node = self.last_node.next def display(self): current = self.head while current is not None: print(current.data, end = ' ') current = current.next def find_index(self, key): current = self.head index = 0 while current: if current.data == key: return index current = current.next index = index + 1 return -1 a_llist = LinkedList() for data in [4, -3, 1, 0, 9, 11]: a_llist.append(data) print('The linked list: ', end = '') a_llist.display() print() key = int(input('What data item would you like to search for? ')) index = a_llist.find_index(key) if index == -1: print(str(key) + ' was not found.') else: print(str(key) + ' is at index ' + str(index) + '.')
1. An instance of LinkedList is created.
2. Some elements are appended to the list.
3. The linked list is displayed.
4. The user is prompted for a key to search.
5. find_index searches for the index. It returns -1 if the key is not found.
6. The index is displayed if found.
Case 1: The linked list: 4 -3 1 0 9 11 What data item would you like to search for? 9 9 is at index 4. Case 2: The linked list: 4 -3 1 0 9 11 What data item would you like to search for? 11 11 is at index 5. Case 3: The linked list: 4 -3 1 0 9 11 What data item would you like to search for? 3 3 was not found.
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