Implementation of a list using a linked list with pointers.

#include <iostream.h>
struct element

{
int number;
element *next;
};

/* the operators declared on the type list.*/
void read(element *&list);
void write(element *list);
int length(element *list);
int position(element *list, int num);
void remove(element *&list,int position);
void insert(element *&list,int new_num,int position);
element *ele(element *list,int position);

void add(int new_num,element *&list,element *this_el);

void main()
{

element *list,*p,*q;
int leng;

read(list);
write(list);
q = ele (list,3);
add (5,list,q);
write(list);
insert(list,10,2);
write(list);
remove(list,4);
write(list);
insert(list,12,1);
write(list);
leng = position(list,10);
cout<< " pos of 10 is " << leng <<endl;
cout<< " The length of the list is: " << length(list)<<endl;
cout<<endl;
]
}
/* reading a list from input */
void read(element *&list)
{
element *p,*last;
list = new element;
p = list;
cout<< " enter a number";
cin>>p->number;
while (!cin.eof())
{
p->next = new element;
last = p;
p = p->next;
cout<< " enter a number ";
cin>>p->number;
}
delete (p);
last->next = NULL;
}

/* writing a list on the output */
void write(element *list)
{
element *p;
cout<<endl;
p = list;
while (p!=NULL)
{
cout<< p->number<<" ";
p=p->next;
}
cout<<endl;
}

/* Gets a list and returns its length */
int length (element *list)
{
element *p;
int count=0;
p=list;
while (p!=NULL)
{
count++;
p = p->next;
}
return count;
}

/*Gets an element and returns its positon in the list. If the element*/
/*is not in the list, returns 0 */

int position(element *list,int num)
{
element *p;
int i=1;
for (p=list;p!=NULL;p=p->next)
{
if ((p->number)==num)
return i;
i++;
}
return 0;
}

/*Gets a number and removes the element that stays in this position */
void remove(element *&list,int position)
{
element *before,*p;
if (position==1)
{
before=list;
list = list->next;
delete (before);
}
else
{
before = ele (list,position-1);
if (before!=NULL)
{
p = before->next;
before->next = p->next;
delete (p);
}
}
}

/* Insert a new element to be the i-th element of the list */
/* the function uses the function add*/
void insert(element *&list,int new_num,int position)
{
element *p;
if (position==1)
add(new_num,list,NULL);
else
{
p = ele(list,position-1);
add(new_num,list,p);
}
}

/* Gets a position in the list and returns a pointer to the element*/
/* in this position*/
element *ele(element *list,int position)
{
element *p=list;
int i;
for (i=1;i<position;i++)
{
if (p==NULL)
return p;
p=p->next;
}
return p;
}

/* Add a new element after a given element.If the given element is NULL*/
/* Add the new element to be the first element*/
void add(int new_num,element *&list,element *this_el)
{
element *p;
if (list==NULL)
{
list = new element;
list->number = new_num;
list->next = NULL;
}
else
{
p = new element;
p->number = new_num;
if (this_el==NULL)
{
p->next = list;
list = p;
}
else
{
p->next=this_el->next;
this_el->next = p;
}
}
}