Counting nodes of a Linked List
Counting the number of nodes of a singly linked list requires maintaining a counter that is initialized to 0 and incremented by 1 each time a node is encountered in the process of traversing a list from the start.
Here is a program that counts the number of nodes in a singly linked chain p, where p is a pointer to the first node in the list.
Example
# include <stdio.h>
# include <stdlib.h>
struct node
{
int data;
struct node *link;
};
struct node *insert(struct node *, int);
int nodecount(struct node*);
void printlist ( struct node * );
struct node *insert(struct node *p, int n)
{
struct node *temp;
if(p==NULL)
{
p=(struct node *)malloc(sizeof(struct node));
if(p==NULL)
{
printf("Error\n");
exit(0);
}
p-> data = n;
p-> link = NULL;
}
else
{
temp = p;
while (temp-> link!= NULL)
temp = temp-> link;
temp-> link = (struct node *)malloc(sizeof(struct node));
if(temp -> link == NULL)
{
printf("Error\n");
exit(0);
}
temp = temp-> link;
temp-> data = n;
temp-> link = NULL;
}
return (p);
}
void printlist ( struct node *p )
{
printf("The data values in the list are\n");
while (p!= NULL)
{
printf("%d\t",p-> data);
p = p-> link;
}
}
/* A function to count the number of nodes in a singly linked list */
int nodecount (struct node *p )
{
int count=0;
while (p != NULL)
{
count ++;
p = p->link;
}
return(count);
}
int main()
{
int n;
int x;
struct node *start = NULL ;
printf("Enter the nodes to be created \n");
scanf("%d",&n);
while ( n-- > 0 )
{
printf( "Enter the data values to be placed in a node\n");
scanf("%d",&x);
start = insert ( start,x);
}
printf("The created list is\n");
printlist ( start );
n = nodecount(start);
printf("The number of nodes in a list are: %d\n",n);
getchar();
return 0;
}
