﻿ C Program: Delete first node of Singly Linked List - w3resource

# C Exercises: Delete first node of Singly Linked List

## C Singly Linked List : Exercise-7 with Solution

Write a program in C to delete the first node of a Singly Linked List.

Pictorial Presentation:

Sample Solution:

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
void FirstNodeDeletion();	    //function to delete the first node
void displayList();             //function to display the list

int main()
{
int n,num,pos;
printf("\n\n Linked List : Delete first node of Singly Linked List :\n");
printf("------------------------------------------------------------\n");
printf(" Input the number of nodes : ");
scanf("%d", &n);
createNodeList(n);
printf("\n Data entered in the list are : \n");
displayList();
FirstNodeDeletion();
printf("\n Data, after deletion of first node : \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 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;
stnode-> nextptr = NULL; //Links the address field to NULL
tmp = stnode;
//Creates n nodes and adds to linked list
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;
}
}
}
}

void FirstNodeDeletion()
{
struct node *toDelptr;
if(stnode == NULL)
{
printf(" There are no node in the list.");
}
else
{
toDelptr = stnode;
stnode = stnode->nextptr;
printf("\n Data of node 1 which is being deleted is :  %d\n", toDelptr->num);
free(toDelptr);  // Clears the memory occupied by first node
}
}

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
}
}
}
```
```

Sample Output:

```Linked List : Delete first node of Singly Linked List :
------------------------------------------------------------
Input the number of nodes : 3
Input data for node 1 : 2
Input data for node 2 : 3
Input data for node 3 : 4

Data entered in the list are :
Data = 2
Data = 3
Data = 4

Data of node 1 which is being deleted is :  2

Data, after deletion of first node :
Data = 3
Data = 4
```

Flowchart:

>

createNodeList():

FirstNodeDeletion() :

displayList() :

C Programming Code Editor:

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