"menu driven program to delete in linked list" Code Answer's

menu driven program to delete in linked list

By ujjwal sotra on May 20, 2021

#include <iostream>

using namespace std;
class node
{
public:
    int data;
    node*next;
};
node*head=NULL;
void insertlist(int val)
{
    node*temp=new node;
    temp->data=val;
    if(head==NULL)
    {
        temp->next=head;
        head=temp;
    }
    else
    {
        temp->next=head;
        head=temp;
    }
}
void delete_start()
{
    if(head==NULL)
    {
        cout<<"no element in the list :: nothing to be deleted:"<<endl;
    }
    else
    {
        node*temp=new node;
        temp=head;
        head=head->next;
        delete(temp);
    }
}
void delete_end()
{
    if(head==NULL)
    {
         cout<<"no element in the list :: nothing to be deleted:"<<endl;
    }
    else
    {
        node *temp=new node;
        temp=head;
        node*ptr=new node;
        while(temp->next->next!=NULL)
        {
            temp=temp->next;
        }
        ptr=temp->next;
        temp->next=NULL;
        delete ptr;


    }
}
void delete_any(int val)
{
    node*temp=new node;
    if(head==NULL)
    {
         cout<<"no element in the list :: nothing to be deleted:"<<endl;
    }
    else
    {
        if(head->data==val)
        {
            temp=head;
            head=head->next;
            delete temp;
        }
        else
        {
            node*ptr=new node;
            ptr=head;
            while(ptr->next!=NULL)
            {
                if(ptr->next->data==val)
                {
                    temp=ptr->next;
                    ptr->next=ptr->next->next;
                    delete temp;
                }
                ptr=ptr->next;

            }
        }
    }

}
void printf()
{
    node*temp=new node;
    temp=head;
    while(temp!=NULL)
    {
        cout<<temp->data<<" ";
        temp=temp->next;
    }
    cout<<endl;
}
int main()
{
    int n;
    int t;
    cin>>t;
    while(t--)
    {
    cout<<"enter the value to be inserted in the list:"<<endl;
    cin>>n;
    insertlist(n);
    }
    printf();
    int s;
    while(1)
    {
        cout<<"1-delete from the start"<<endl<<"2-delete from the end"<<endl<<"3-delete any element"<<endl<<"4-exit"<<endl;
        cout<<"enter your choice:"<<endl;
        cin>>s;
        switch(s)
            {
            case 1:
                {
                   delete_start();
                   printf();
                   break;
                }
            case 2:
                {
                    delete_end();
                    printf();
                    break;
                }
            case 3:
                {
                    int a;
                    printf();
                    cout<<"enter the value to be deleted:"<<endl;
                    cin>>a;
                    delete_any(a);
                    printf();
                    break;
                }
            case 4:
                {
                    exit(0);
                }
            default:
                {
                    cout<<"invalid opertaion:"<<endl;
                }
            }

    }
    return 0;
}

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