How do you insert a node using doubly linked list in c plus plus?

Answer 1

#include<iostream>

#include<list>

void print_list (std::list<int>& list)

{

for (std::list<int>::const_iterator it=list.begin(); it!=list.end(); ++it)

std::cout << *it << ", ";

std::cout << "\b\b \n";

}

int main()

{

// instantiate a list

std::list<int> list;

// push a new value onto the back of the list:

list.push_back (1);

print_list (list);

// push a new value onto the front of the list:

list.push_front (2);

print_list (list);

// insert a new value at the back of the list

list.insert (list.end(), 3);

print_list (list);

// insert a new value at the front of the list

list.insert (list.begin(), 4);

print_list (list);

// locate value 1.

std::list<int>::const_iterator it=list.begin();

while (it!=list.end() && *it != 1)

++it;

// insert a new value in front of value 1.

list.insert (it, 5);

print_list (list);

}

Output:

1

2, 1

2, 1, 3

4, 2, 1, 3

4, 2, 5, 1, 3

Answer 2

In order to insert a new node you must first determine where the node will be inserted. For instance, in an unbalanced binary tree (sorting tree), you will traverse from the root node, comparing its data to the data you wish to insert. If the data to be inserted is greater then you traverse to its right node, otherwise you traverse to its left node. You repeat this process for each node you traverse to until there is no node to traverse to. You then create a new node for the data and assign the current node's left or right pointer to the new node. That is, if the data is greater than the current node, and the current node's right node is NULL, the new node becomes the current node's right node. You then start at the root to insert the next node.