linked list 3

/Write a program to implement a linked list using structure and functions (make a new node, insert first, insert last, insert middle(insert after a value n), delete first, delete last, delete middle(delete node contain value m), and display(print elements of node).
/
#include <iostream>
using namespace std;
#include<stdlib.h>
struct node
{
int number;
node next;
};
//Make new node
node make_new_node(int x)
{
node* p;
p = new node;
p->number = x;
p->next = NULL;
return p;
}
//Insert in begining
node* insert_begin(node* p)
{
int x;
cout << "Enter value in new node \n";
cin >> x;
node* temp;
temp = make_new_node(x);
temp->next = p;
p = temp;
return p;
}
//insert in last
node* insert_last(node* p)
{
int x;
cout << "Enter value in new node \n";
cin >> x;
node* curr, * temp;
if (p == NULL)
p = make_new_node(x);
else
{
curr = p;
while (curr->next != NULL)
curr = curr->next;
temp = make_new_node(x);
curr->next = temp;

}

return p; }
// insert value (x) after a node contain the value (n) or in last if (n) is not exist
node* insert_middle(node* p, int n)
{
int x;
cout << "Enter value in new node \n";
cin >> x;
node* curr, * temp;
if (p == NULL)
p = make_new_node(x);
else {

curr = p;
while (curr->number != n && curr->next != NULL)
curr = curr->next;
temp = make_new_node(x);
temp->next = curr->next;
curr->next = temp;
}
return p;

}
//Delete first node
node* delete_first(node* p)
{
if (p == NULL)
{
cout << "No nodes found \n";
return NULL;
}
else
{
node* first;
first = p;
p = p->next;
delete first;
}
return p;

}
//Delete last node
node* delete_last(node* p)
{
node* curr, * d;
if (p == NULL)
{
cout << "No nodes found \n";
return NULL;
}
curr = p;
while (curr->next->next != NULL)
curr = curr->next;
d = curr->next;
curr->next = NULL;
delete d;
return p;
}
//Delete "node" after the node contains the value (n) or last node if n is not exist
node* delete_middle(node* p, int m)
{
node* curr, * d;
curr = p;
while (curr->next->number != m && curr->next->next != NULL)
curr = curr->next;
d = curr->next;
curr->next = d->next;
delete d;
return p;
}
//Display (print) node elements
void display_list(node* p)
{
node* curr;
if (p == NULL)
cout << "No nodes found \n";
else
{
cout << "\n Data in the nodes are:\n";
curr = p;
while (curr != NULL)
{
cout << curr->number << "\n";
curr = curr->next; }
}
}
int main()
{
node* p;
p = NULL;
int ch;
int x, n, m;
cout << "\n 1.Make a node. \n 2.Insert first. \n 3.Insert last. \n 4.Insert middle. \n 5.Delete first. \n 6.Delete last. \n 7.Delete middle. \n 8.Display \n 9.Exit program \n";
do {
cout << "Enter your choice";
cin >> ch;
switch (ch)
{
case 1: cout << "Enter x value to make a new node. \n";
cin >> x;
p = make_new_node(x); break;
case 2: p = insert_begin(p); break;
case 3: p = insert_last(p); break;
case 4: cout << "\n Enter a value (n) to insert a node middle after it: ";
cin >> n;
p = insert_middle(p, n); break;
case 5: p = delete_first(p); break;
case 6: p = delete_last(p); break;
case 7:cout << "\n Enter a value of (m) to delete a middle node: ";
cin >> m;
p = delete_middle(p, m); break; case 8: display_list(p); break;
case 9: exit(0); break;
default: cout << "\n Invalid choice."; }
} while (ch != 9);
return 0; }