Double Linked List Insert ,Remove,Search,Print in C++.

#include <iostream>

using namespace std;

struct list

{

    int data;

    struct list* next;

    struct list* prev;

};

typedef struct list node;

node *head=NULL;

int flag=1;

void insert_x_y()

{

    int x,y,f=0;

    node *temp=head,*back_,*t;

    cout<<"Please Enter x and y: "<<endl;

    cin>>x;

    cin>>y;

    if(temp==NULL)

    {

        head = new node();

        head->data=y;

        head->next=NULL;

        head->prev= NULL;

        ///back_ = head;

        cout<<"INSERT after dummy node."<<endl;

    }

    else

    {

        while(temp->next!=NULL)

        {

            if(temp->data==x)

            {

                f=1;

                break;

            }

            temp=temp->next;

        }

        if(f==1)

        {

            t =new node();

            t->data=y;

            t->next = temp->next;

            temp->next->prev = t;

            t->prev = temp;

            temp->next = t;

            cout<<"INSERT after "<<x<<endl;

        }

        else

        {

             cout<<"INSERT after dummy node."<<endl;

            t =new node();

            t->data=y;

            t->next = head;

            t->prev = NULL;

            head->prev = t;

            head=t;

        }

    }

}

void print_node()

{

    node *temp=head;

    if(temp==NULL)

    {

        cout<<" 
No Data Found 
"<<endl;

        return;

    }

    while(temp!=NULL)

    {

        cout<<temp->data<<" ";

        temp = temp->next;

    }

}

void delete_node()

{

    int x,flag=0;

    node *temp=head;

    cout<<"Enter The Value You Want to Delete: ";

    cin>>x;

    while(temp!= NULL)

    {

        if(temp->data==x)

        {

            flag=1;

            break;

        }

        if(flag==1)break;

        temp=temp->next;

    }

    if(flag==1)

    {

        cout<<"Node with key value "<<x<<" is DELETED."<<endl;

        if(head->data==x)

        {

            head = temp->next;

            temp->prev=NULL;

        }

        else

        {

            temp->next->prev=temp->prev;

            temp->prev->next = temp->next;

        }

        delete(temp);

    }

    else

    {

        cout<<"
DELETE not possible. "<<endl;

    }

}

void search_node()

{

    int x,flag=0;

    node *temp=head;

    cout<<"Enter The Value You Want to Search: ";

    cin>>x;

    while(temp->next != NULL)

    {

        if(temp->data==x)

        {

            cout<<"
Node with key value "<<x<<" is FOUNDED. "<<endl;

            return;

        }

        temp = temp->next;

    }

    cout<<"
Not FOUND. "<<endl;

    return;

}

int menu()

{

    int n;

    cout<<"
Press 1 for Insert command
Press 2 for remove command
Press 3 for search command
Press 4 for show all command
Press 5 for exit command"<<endl;

    cin>>n;

    if(n==1)

    {

        insert_x_y();

    }

    else if(n==2)

    {

        delete_node();

    }

    else if(n==3)

    {

        search_node();

    }

    else if(n==4)

    {

        print_node();

    }

    else if(n==5)

    {

        flag=0;

        return 0;

    }

    else

    {

        cout<<"
Wrong Input"<<endl;

        menu();

    }

}

int main()

{

    while(1)

    {

        if(flag==1)

            menu();

        else break;

    }

    return 0;

}