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C Programming Exercises

C Exercises: Delete a node from the middle of Singly Linked List

C Linked List : Exercise-8 with Solution

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

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 MiddleNodeDeletion(int pos);	//function to delete a node from middle
void displayList();             	//function to display the list

int main()
{
    int n,num,pos;
		printf("\n\n Linked List : Delete a node from the middle 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();
    
    printf("\n Input the position of node to delete : ");
    scanf("%d", &pos);

    if(pos<=1 || pos>=n)
    {
     printf("\n Deletion can not be possible from that position.\n ");
    }
	      if(pos>1 && pos<n)
      {
       printf("\n Deletion completed successfully.\n ");
	   MiddleNodeDeletion(pos);
      }

	    printf("\n The new list are  : \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 MiddleNodeDeletion(int pos)
{
    int i;
    struct node *toDelMid, *preNode;
 
    if(stnode == NULL)
    {
        printf(" There are no nodes in the List.");
    }
    else
    {
        toDelMid = stnode;
        preNode = stnode;
 
        for(i=2; i<=pos; i++)
        {
            preNode = toDelMid;
            toDelMid = toDelMid->nextptr;
 
            if(toDelMid == NULL)
                break;
        }
        if(toDelMid != NULL)
        {
            if(toDelMid == stnode)
                stnode = stnode->nextptr;
 
            preNode->nextptr = toDelMid->nextptr;
            toDelMid->nextptr = NULL;
            free(toDelMid);
        }
        else
        {
            printf(" Deletion can not be possible from that position.");
        }
    }
}

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 a node from the middle of Singly Linked List. :                                         
-------------------------------------------------------------------------                                     
 Input the number of nodes : 3                                                                                
 Input data for node 1 : 2                                                                                    
 Input data for node 2 : 5                                                                                    
 Input data for node 3 : 8                                                                                    
                                                                                                              
 Data entered in the list are :                                                                               
 Data = 2                                                                                                     
 Data = 5                                                                                                     
 Data = 8                                                                                                     
                                                                                                              
 Input the position of node to delete : 2                                                                     
                                                                                                              
 Deletion completed successfully.                                                                             
                                                                                                              
 The new list are  :                                                                                          
 Data = 2                                                                                                     
 Data = 8

Flowchart:

Flowchart: Delete a node from the middle of Singly Linked List

createNodeList() :

Flowchart: Delete a node from the middle of Singly Linked List

MiddleNodeDeletion() :

Flowchart: Delete a node from the middle of Singly Linked List

displayList() :

Flowchart: Delete a node from the middle of Singly Linked List

C Programming Code Editor:

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