严重错误：ll.h：无此类文件或目录

Question

I have two files ll.cpp and ll.h both in the same directory.

ll.cpp

  #include <ll.h>

#include <iostream>

using namespace std;




    template <class t>
    LinkedL<t>::LinkedL()
     {
        flag=0;
        head=NULL;
        tail=NULL;
        curr=0;
    }
    template <class t>
    LinkedL<t>::void insertS(t inf)
    {
        Node<t> *n=new Node<t>;
        n->next=head;
        n->data=inf;
        head=n;
        if(curr==0)
            tail=n;
        curr++;
        //cout<<curr<<"\n";
    }
    template <class t>
    LinkedL<t>::void insertE(t inf)
    {
        Node<t> *n=new Node<t>;
        n->next=NULL;
        n->data=inf;
        if(curr!=0)
        tail->next=n;
        tail=n;
        if(curr==0)
            head=n;
        curr++;
        //cout<<curr<<"\n";
    }
    template <class t>
    LinkedL<t>::t delS()
    {
        if(curr>=1)
        {
            flag=1;
            t temp=head->data;
            Node<t> *n=head;
            head=head->next;
            if(head==NULL)
                tail=NULL;
            delete n;
            curr--;
            return temp;
        }
        else
        {
            cout<<"EMPTY LIST\n";
        }
    }
    template <class t>
    LinkedL<t>::t delE()
    {

        if(curr>=1)
        {
            flag=1;
            Node<t> *n=head;
            t temp;
            if(curr>1)
            {
                while(n->next!=tail)
                    {   
                        //cout<<n->data<<" ";
                        n=n->next;
                    }
                    //cout<<"\n";
                Node<t> *n1=tail;
                temp=n1->data;
                tail=n;
                tail->next=NULL;
                //cout<<n->data<<"\n";
                delete n1;
                }
                else if(curr==1)
                {
                    temp=tail->data;
                    delete tail;
                    head=NULL;
                    tail=NULL;
                }

                curr--;
                //cout<<curr<<"\n";
                return temp;
        }else if(curr==0)
        {
            cout<<"EMPTY LIST\n";
        }

    }
    template <class t>
    LinkedL<t>::bool search(t inf)
    {
        Node<t> *n=head;
        while(n!=NULL && n->data!=inf)
            n=n->next;
        if(n==NULL)
            return false;
        return true;
    }
    template <class t>
    LinkedL<t>::void traverse()
    {
        if(curr!=0)
        {
            Node<t> *n=head;
            while(n!=NULL)
                {
                cout<<n->data<<" ";
                n=n->next;
                }
            cout<<'\n';
        }
        else
        {
            cout<<"EMPTY\n";
        }
    }
    template <class t>
    LinkedL<t>::bool isEmpty()
    {
        if(curr==0)
            return true;
        return false;
    }
    template <class t>
    LinkedL<t>::t at(int i)
    {
        if(i<=curr)
        {
            flag=1;
            Node<t> *n=head;
            int k=1;
            while(k!=i)
            {
                n=n->next;
                k++;
            }
            return n->data;
        }
        else
            cout<<"Invalid Index\n";
    }
    template <class t>
    LinkedL<t>::void insert(int i,t dat)
    {
        if(i<=curr+1)
        {
            flag=1;
            if(curr==0 || i==1)
            {
                insertS(dat);
            }
            else
            {
                Node<t> *n1=NULL;
                Node<t> *n=head;
                int k=1;
                while(k!=i)
                {
                    n1=n;
                    n=n->next;
                    k++;
                }
                Node<t> *temp=new Node<t>;
                temp->next=n;
                n1->next=temp;
                temp->data=dat;
                curr++;
            }
        }
        else
            cout<<"Invalid Index\n";
    }
    template <class t>
    LinkedL<t>::void reverse()
    {
        if(curr!=0)
        {
            Node<t> *n=head;
            Node<t> *n1=head;
            Node<t> *n2=NULL;
            while(n!=NULL)
            {
                n1=n->next;
                n->next=n2;
                n2=n;
                n=n1;
            }
            n=head;
            head=tail;
            tail=n;
        }
    }
    template <class t>
    LinkedL<t>::t delet(int i)
    {
        Node<t> *n=head;
        if(head!=NULL && i<=curr)
        {
            flag=1;
            t dat;
            int k=1;
            if(i==1)
                dat=delS();
            else
            {
                while(k!=i-1)
                    {
                        n=n->next;
                        k++;
                    }
                Node<t> *n1=n->next;
                n->next=n->next->next;
                dat=n1->data;
                delete n1;
            }
            curr--;
            return dat;
        }
        else
        {
            cout<<"Invalid Index\n";
        }
    }

ll.h

   #ifndef LL_H
#define LL_H

template <class t>
class Node
{
    public:
    Node<t> * next;
    t data;
};


template <class t>
class LinkedL
{
    private:
        Node<t>* head;
        Node<t>* tail;
        int curr;
    public:
     int flag; 
     LinkedL();

    void insertS(t inf);

    void insertE(t inf);

    t delS();

    t delE();

    bool search(t inf);

    void traverse();


    bool isEmpty();

    t at(int i);

    void insert(int i,t dat);

    void reverse();

    t delet(int i);


};
#endif

I am not able to figure out why the compiler is giving this error. Same thing is happening for all the .h and .cpp pairs as a crosscheck I changed the permission to rwx for all users but still the same error is coming. Please help.

Answer 1

If you include something and write it with <> the preprocessor is searching in external libraries like the std library. Similar to what you did here:

#include <iostream>

But if you include your own .cpp or .h files use "" so it will search in your local directory. Therefore, use in this case:

#include "ll.h"