C++ Linked List Exercises: Insert a node at any position of a Singly Linked List
9. Insert Node at Any Position in Singly Linked List
Write a C++ program to insert a new node at any position of a Singly Linked List.
Test Data:
Original list:
7 5 3 1
Position: 1, Value: 12
Updated list:
12 7 5 3 1
Position: 4, Value: 14
Updated list:
12 7 5 14 3 1
Position: 7, Value: 18
Updated list:
12 7 5 14 3 1 18
Sample Solution:
C++ Code:
#include <iostream> // Including input-output stream header file
using namespace std; // Using standard namespace
// Structure for defining a Node
struct Node {
int num; // Data field to store a number
Node *next; // Pointer to the next node
}; // Node constructed
int sizen = 0; // Initializing variable to keep track of the size of the linked list
// Function to insert a node at the beginning of the linked list
void insert(Node** head, int num) {
Node* new_Node = new Node(); // Creating a new node
new_Node->num = num; // Assigning data to the new node
new_Node->next = *head; // Pointing the new node to the current head
*head = new_Node; // Making the new node as the head
sizen++; // Increasing the size of the linked list
}
// Function to insert a node at a given position in the linked list
void insert_Position(int pos, int data, Node** head) {
Node* new_node = new Node(); // Creating a new node
new_node->num = data; // Assigning data to the new node
new_node->next = NULL; // Initializing next pointer to NULL
// Invalid positions
if (pos < 1 || pos > sizen + 1) {
cout << "Invalid\n";
} else if (pos == 1) { // Inserting at the beginning
new_node->next = *head;
*head = new_node;
sizen++;
} else {
Node* temp = *head;
// Traverse till the (pos-1)th node
while (--pos > 1) {
temp = temp->next;
}
new_node->next = temp->next;
temp->next = new_node;
sizen++;
}
}
// Display all nodes in the linked list
void display_all_nodes(Node* node) {
while (node != NULL) {
cout << node->num << " "; // Displaying the data in the current node
node = node->next; // Move to the next node
}
}
int main() {
Node* head = NULL; // Initializing the head of the linked list as NULL
insert(&head, 1); // Inserting a node with value 1
insert(&head, 3); // Inserting a node with value 3
insert(&head, 5); // Inserting a node with value 5
insert(&head, 7); // Inserting a node with value 7
cout << "Original list:\n"; // Displaying message for the original list
display_all_nodes(head); // Displaying all nodes in the original list
int pos = 1, value = 12;
cout << "\n\nPosition: " << pos << ", Value: " << value;
insert_Position(pos, value, &head); // Inserting a node at a specific position
cout << "\nUpdated list:\n";
display_all_nodes(head); // Displaying all nodes in the updated list
pos = 4, value = 14;
cout << "\n\nPosition: " << pos << ", Value: " << value;
insert_Position(pos, value, &head); // Inserting a node at a specific position
cout << "\nUpdated list:\n";
display_all_nodes(head); // Displaying all nodes in the updated list
pos = 7, value = 18;
cout << "\n\nPosition: " << pos << ", Value: " << value;
insert_Position(pos, value, &head); // Inserting a node at a specific position
cout << "\nUpdated list:\n";
display_all_nodes(head); // Displaying all nodes in the updated list
cout << endl; // Displaying newline
return 0; // Returning from the main function
}
Sample Output:
Original list: 7 5 3 1 Position: 1, Value: 12 Updated list: 12 7 5 3 1 Position: 4, Value: 14 Updated list: 12 7 5 14 3 1 Position: 7, Value: 18 Updated list: 12 7 5 14 3 1 18
Flowchart:
For more Practice: Solve these Related Problems:
- Write a C++ program to insert a node at a given position in a singly linked list and display the resulting list.
- Develop a C++ program that takes a position and value from the user to insert a node at that position in a singly linked list.
- Design a C++ program to insert nodes at multiple positions in a singly linked list based on a series of user inputs.
- Implement a C++ program to insert a node at a specific position in a singly linked list and then verify the list integrity by re-traversing it.
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Previous C++ Exercise: Get Nth node in a Singly Linked List.
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