# C Exercises: Create a singly linked list and count the number of nodes

## C Linked List : Exercise-3 with Solution

Write a program in C to create a singly linked list of n nodes and count the number of nodes.
Test Data :
Input the number of nodes : 3
Input data for node 1 : 5
Input data for node 2 : 6
Input data for node 3 : 7
Expected Output :

``` Data entered in the list are :
Data = 5
Data = 6
Data = 7

Total number of nodes = 3
```

C Code:

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

struct node
{
int num;                    //Data of the node
struct node *nextptr;       //Address of the node
}*stnode;

void createNodeList(int n);     //function to create the list
int NodeCount();	            //function to count the nodes
void displayList();             //function to display the list

int main()
{
int n,totalNode;
printf("\n\n Linked List : Create a singly linked list and count the number of nodes :\n");
printf("------------------------------------------------------------------------------\n");
printf(" Input the number of nodes : ");
scanf("%d", &n);
createNodeList(n);
printf("\n Data entered in the list are : \n");
displayList();
totalNode = NodeCount();
printf("\n Total number of nodes = %d\n", totalNode);
return 0;
}
void createNodeList(int n)
{
struct node *fnNode, *tmp;
int num, i;
stnode = (struct node *)malloc(sizeof(struct node));
if(stnode == NULL) //check whether the stnode is NULL and if so no memory allocation
{
printf(" Memory can not be allocated.");
}
else
{
// reads data for the node through keyboard
printf(" Input data for node 1 : ");
scanf("%d", &num);
stnode-> num = num;
tmp = stnode;
for(i=2; i<=n; i++)
{
fnNode = (struct node *)malloc(sizeof(struct node));
if(fnNode == NULL) //check whether the fnnode is NULL and if so no memory allocation
{
printf(" Memory can not be allocated.");
break;
}
else
{
printf(" Input data for node %d : ", i);
scanf(" %d", &num);
fnNode->num = num;      // links the num field of fnNode with num
fnNode->nextptr = NULL; // links the address field of fnNode with NULL
tmp->nextptr = fnNode; // links previous node i.e. tmp to the fnNode
tmp = tmp->nextptr;
}
}
}
}

int NodeCount()
{
int ctr = 0;
struct node *tmp;
tmp = stnode;
while(tmp != NULL)
{
ctr++;
tmp = tmp->nextptr;
}
return ctr;
}
void displayList()
{
struct node *tmp;
if(stnode == NULL)
{
printf(" No data found in the list.");
}
else
{
tmp = stnode;
while(tmp != NULL)
{
printf(" Data = %d\n", tmp->num);   // prints the data of current node
tmp = tmp->nextptr;                 // advances the position of current node
}
}
}
```

Flowchart :

createNodeList() :

NodeCount() :

displayList() :

C Practice online:

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

struct node
{
int num;                    //Data of the node
struct node *nextptr;       //Address of the node
}*stnode;

void createNodeList(int n);     //function to create the list
int NodeCount();	            //function to count the nodes
void displayList();             //function to display the list

int main()
{
int n,totalNode;
printf("\n\n Linked List : Create a singly linked list and count the number of nodes :\n");
printf("------------------------------------------------------------------------------\n");
printf(" Input the number of nodes : ");
scanf("%d", &n);
createNodeList(n);
printf("\n Data entered in the list are : \n");
displayList();
totalNode = NodeCount();
printf("\n Total number of nodes = %d\n", totalNode);
return 0;
}
void createNodeList(int n)
{
struct node *fnNode, *tmp;
int num, i;
stnode = (struct node *)malloc(sizeof(struct node));
if(stnode == NULL) //check whether the stnode is NULL and if so no memory allocation
{
printf(" Memory can not be allocated.");
}
else
{
// reads data for the node through keyboard
printf(" Input data for node 1 : ");
scanf("%d", &num);
stnode-> num = num;
tmp = stnode;
for(i=2; i<=n; i++)
{
fnNode = (struct node *)malloc(sizeof(struct node));
if(fnNode == NULL) //check whether the fnnode is NULL and if so no memory allocation
{
printf(" Memory can not be allocated.");
break;
}
else
{
printf(" Input data for node %d : ", i);
scanf(" %d", &num);
fnNode->num = num;      // links the num field of fnNode with num
fnNode->nextptr = NULL; // links the address field of fnNode with NULL
tmp->nextptr = fnNode; // links previous node i.e. tmp to the fnNode
tmp = tmp->nextptr;
}
}
}
}

int NodeCount()
{
int ctr = 0;
struct node *tmp;
tmp = stnode;
while(tmp != NULL)
{
ctr++;
tmp = tmp->nextptr;
}
return ctr;
}
void displayList()
{
struct node *tmp;
if(stnode == NULL)
{
printf(" No data found in the list.");
}
else
{
tmp = stnode;
while(tmp != NULL)
{
printf(" Data = %d\n", tmp->num);   // prints the data of current node
tmp = tmp->nextptr;                 // advances the position of current node
}
}
}
```

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