Linked List implementation in C++

The more detailed explanation of linked list and its implementation in C, C++, Java, and Pythion is given here.

Algorithm for adding an element  (data) to the front of the list.

Insertion new node at the end.

Deletion of the first node

Deletion of the last node

The source code in C++ for whole process include inserting and deleting elements before and after the given node is given below:

#include<iostream>
#include<cstdlib>
using namespace std;
struct node{
    int info;
    struct node *next;
};
class Link{
     node *list;
    public:
        Link();
        void insert_at_begining(int);
        void insert_at_end(int);
        void insert_before_node();
        void insert_after_node();
        void delete_at_begining();
        void delete_at_end();
        void delete_before_node();
        void delete_before_after_node(int);
        node *find_before_node(node*);
        void display();
};
Link::Link(){
    list = NULL;
}
node *Link::find_before_node(node *p){
    int count = 0;
    int count1 = 0;
    node *temp = new node;
    temp = list;
    while(temp!=p){
        count++;
        temp=temp->next;
    }
    temp = list;
    while(count1<count-1){
        count1++;
        temp = temp->next;
    }
    return temp;
}
void Link::insert_at_begining(int data){
    node *p = new node;
    p->info = data;
    p->next = list;
    list = p;
}
void Link::insert_at_end(int data){
    node *p = new node;
    node *r = new node;
    node *q = new node;
    r = list;
    p->info = data;
    p->next = NULL;
    if(list == NULL){
        list = p;
    }else{
        while(r->next!=NULL){
            r = r->next;
        }
        r->next = p;
    }
}
void Link::insert_before_node(){
    node *p = new node;
    node *l = new node;
    node *r = new node;
    int data1, data2;
    bool isFound = false;
    cout<<"Enter the node: ";
    cin>>data1;
    p = list;
    while(p != NULL){
        if(p->info == data1){
            isFound = true;
            break;
        }
        l = p;
        p = p->next;
    }
    if(isFound){
        cout<<"Enter the data to insert:";
        cin >> data2;
        r->info = data2;
        if(p==list){
            insert_at_begining(data2);
        }else{
            l->next = r;
            r->next = p;
        }
    }else{
        cout<<"\nMember not found\n";
    }
}
void Link::insert_after_node(){
    node *p = new node;
    node *r = new node;
    node *l = new node;
    int data1, data2;
    bool isFound = false;
    cout<<"Enter the node: ";
    cin>>data1;
    p = list;
    while(p!= NULL){
        if(p->info == data1){
            isFound = true;
            break;
        }
        p = p->next;
    }
    if(isFound){
        cout<<"Enter the data to insert: ";
        cin>>data2;
        r->info = data2;
        if(p->next == NULL){
            insert_at_end(data2);
        }else{
            l = p->next;
            p->next = r;
            r->next = l;
        }
    }else{
        cout<<"\nMember not found\n";
    }
}
void Link::delete_at_begining(){
    node *p = new node;
    if(list == NULL){
        cout<<"\nList is Empty\n";
    }else{
        p = list;
        list = list->next;
        delete p;
    }
}
void Link::delete_at_end(){
  node *p = new node;
  node *l = new node;
  if(list == NULL){
    cout<<"\nList is Empty\n";
  }else{
    p = list;
    if(p->next == NULL){
        list = NULL;
        delete p;
    }else{
        while(p->next!= NULL){
            l = p;
            p = p->next;
        }
        l->next = NULL;
        delete p;
    }
  }
}
void Link::delete_before_node(){
    node *p = new node;
    node *l = new node;
    int data1;
    bool isFound = false;
    p = list;
    cout<<"Enter the node: ";
    cin>>data1;
    if(p == NULL){
        cout<<"\nList is Empty"<<endl;
        exit(0);
    }
    while(p!=NULL){
        if(p->info == data1){
            isFound = true;
            break;
        }
        l = p;
        p = p->next;
    }
    if(isFound){
        if(p == list){
            cout<<"\nIt is the first element\n";
        }else if(p == list->next){
            list = p;
            delete l;
        }else{
            find_before_node(l)->next = p;
            delete l;
        }
    }
}
void Link::display(){
    node *p = new node;
    p = list;
    if(list==NULL){
        cout<<"\nNothing to Display\n";
    }else{
        cout<<"\nThe contents of list\n";
        while(p!=NULL){
            cout<<p->info<<endl;
            p = p->next;
        }
    }
}
int main(){
    int choice;
    Link link;
    while(1){
        int data;
        cout<<"\n1. Insert at the begining"<<endl;
        cout<<"2. Insert at the end"<<endl;
        cout<<"3. Insert before node"<<endl;
        cout<<"4. Insert After node"<<endl;
        cout<<"5. Delete first element"<<endl;
        cout<<"6. Delete last element"<<endl;
        cout<<"7. Delete before node"<<endl;
        cout<<"8. Delete after node"<<endl;
        cout<<"9. Display"<<endl;
        cout<<"10. Exit"<<endl;
        cout<<"Enter the option: ";
        cin>>choice;
        switch(choice){
            case 1:
                cout<<"\nEnter data to Insert: ";
                cin>>data;
                link.insert_at_begining(data);
                break;
            case 2:
                cout<<"Enter data to Insert: ";
                cin>>data;
                link.insert_at_end(data);
                break;
            case 3:
                link.insert_before_node();
                break;
            case 4:
                link.insert_after_node();
                break;
            case 5:
                link.delete_at_begining();
                break;
            case 6:
                link.delete_at_end();
                break;
            case 7:
                link.delete_before_node();
                break;
            case 8:
                //link.delete_before_after_node(0);
                break;
            case 9:
                link.display();
                break;
            case 10:
                exit(0);
                break;
        }
    }
    return 0;
}