C Program to Create a Singly Linked List & Display the Elements in the List using function

About the program

Linked list as we know is  an ordered set of data elements, each containing a link to its successor.

Program

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

struct node 
{
    int num;                        
    struct node *nextptr;           
}*stnode;

void createNodeList(int n); 
void displayList();         

int main()
{
    int n;
		printf("\n\n Singly Linked List\n");
		
    printf(" Input the number of nodes : ");
    scanf("%d", &n);
    createNodeList(n);
    printf("\n Data entered in the list : \n");
    displayList();
    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 fnnode 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;      
        stnode->nextptr = NULL; 
        tmp = stnode;
// Creating n nodes and adding to linked list
        for(i=2; i<=n; i++)
        {
            fnNode = (struct node *)malloc(sizeof(struct node));
            if(fnNode == NULL)
            {
                printf(" Memory can not be allocated.");
                break;
            }
            else
            {
                printf(" Input data for node %d : ", i);
                scanf(" %d", &num);
 
                fnNode->num = num;      
                fnNode->nextptr = NULL; 
 
                tmp->nextptr = fnNode; 
                tmp = tmp->nextptr; 
            }
        }
    }
}
void displayList()
{
    struct node *tmp;
    if(stnode == NULL)
    {
        printf(" List is empty.");
    }
    else
    {
        tmp = stnode;
        while(tmp != NULL)
        {
            printf(" Data = %d\n", tmp->num);       
            tmp = tmp->nextptr;                     
        }
    }
}  

Output

Linked List                                                  
 Input the number of nodes : 5                                                                                
 Input data for node 1 : 5                                                                                    
 Input data for node 2 : 6                                                                                    
 Input data for node 3 : 7                                                                                    
 Input data for node 4 : 8
 Input data for node 5 : 9                                                                                                                    
 Data entered in the list :                                                                                   
 Data = 5                                                                                                     
 Data = 6                                                                                                     
 Data = 7
 Data = 8
 Data = 9