C program to count total number of nodes in Singly Linked List

Write a C program to create a singly linked list of n nodes and count total number of nodes in given linked list. How to count total number of nodes in a linked list in C. Algorithm to count total nodes in a singly linked list. Required knowledge

Basic C programming, Functions, Singly Linked List, Dynamic memory allocation

Algorithm to count number of nodes in Singly Linked List

Algorithm to count number of nodes in Singly Linked List
Begin:
count ← 0
While (temp != NULL) do
countcount + 1
temptemp.next
End while
End if
write ('Total nodes in list =' + count)
End

Program to count number of nodes in Singly Linked List

/**
* C program to count number of nodes of Singly Linked List
*/

#include <stdio.h>
#include <stdlib.h>

/* Structure of a node */
struct node {
int data;          // Data

void createList(int n);
int countNodes();
void displayList();

int main()
{
int n, total;

/*
* Create a singly linked list of n nodes
*/
printf("Enter the total number of nodes: ");
scanf("%d", &n);
createList(n);

printf("\nData in the list \n");
displayList();

/* Count number of nodes in list */
total = countNodes();

printf("\nTotal number of nodes = %d\n", total);

return 0;
}

/*
* Create a list of n nodes
*/
void createList(int n)
{
struct node *newNode, *temp;
int data, i;

head = (struct node *)malloc(sizeof(struct node));

/*
* If unable to allocate memory for head node
*/
{
printf("Unable to allocate memory.");
}
else
{
/*
* Read data of node from the user
*/
printf("Enter the data of node 1: ");
scanf("%d", &data);

/*
*/
for(i=2; i<=n; i++)
{
newNode = (struct node *)malloc(sizeof(struct node));

/* If memory is not allocated for newNode */
if(newNode == NULL)
{
printf("Unable to allocate memory.");
break;
}
else
{
printf("Enter the data of node %d: ", i);
scanf("%d", &data);

newNode->data = data; // Link the data field of newNode with data
newNode->next = NULL; // Link the address field of newNode with NULL

temp->next = newNode; // Link previous node i.e. temp to the newNode
temp = temp->next;
}
}

}
}

/*
* Counts total number of nodes in the list
*/
int countNodes()
{
int count = 0;
struct node *temp;

while(temp != NULL)
{
count++;
temp = temp->next;
}

return count;
}

/*
* Displays the entire list
*/
void displayList()
{
struct node *temp;

/*
* If the list is empty i.e. head = NULL
*/
{
printf("List is empty.");
}
else
{
while(temp != NULL)
{
printf("Data = %d\n", temp->data); // Print data of current node
temp = temp->next;                 // Move to next node
}
}
}

Output

Enter the total number of nodes: 5
Enter the data of node 1: 10
Enter the data of node 2: 20
Enter the data of node 3: 30
Enter the data of node 4: 40
Enter the data of node 5: 50

Data in the list
Data = 10
Data = 20
Data = 30
Data = 40
Data = 50

Total number of nodes = 5

Happy coding 😉 