Question

C Programming Files..

A file has lines of text and on each there are 3 integers. How to extract each of them from all lines and store in a linked list?

Answer 1

/*Source code of the above said program is given below*/

/*NOTE: If you want to change something , please let me know through comments; I will surely revert back to you.*/

/*Assumption: input file name is given here as inputData.txt; the file contents multiple lines and each line contains 3 integers and file is ended with a new blank line.*/

#include <stdio.h>

#include <stdlib.h>

// A linked list node

typedef struct Node

{

int data;

struct Node *next;

}node;

/*Create a node,returns a pointer to that node*/

node *makeNode(int val)

{

/* allocate node */

node* newNode = (node*) malloc(sizeof(node));

/* put in the data */

newNode->data = val;

/*set next as NULL*/

newNode->next = NULL;

  

return newNode;

}

/*Inserts a new node at the end of the list and return head*/

node *insert(node *head, node *newNode)

{

//declare a temp node

node* temp=head;

/* Make next of new node NULL */

newNode->next = NULL;

/* If the Linked List is empty, then make the new node as head */

if(head==NULL)

{

head=newNode;

return head;

}

/*Else move a temp pointer to point to the last node */

while (temp->next != NULL)

temp = temp->next;

/* Change the next of last node */

temp->next = newNode;

/*Return head*/

return head;

}

// Prints contents of linked list starting from head

void printList(node *head)

{

while (head != NULL)

{

printf("%d ", head->data);

head = head->next;

}

}

int main()

{

/*Declaring necessary variables*/

int i;

node *head=NULL;

node *newNode;

//Declare and initialize a filename variable

char file_name[]="inputData.txt";//input file

//Opening input file

FILE* file = fopen (file_name, "r");

//Checking if file can be opened successfully

if(!file)

{

printf("Input File named %s cannot be opened",file_name);

exit(1);

}  

//Reading integer data from file

fscanf (file, "%d", &i);   

while (!feof (file))

{  

//Creating a new node with value of i

newNode=makeNode(i);

//Inserting new node into link list

head=insert(head,newNode);

//Reading data from file

fscanf (file, "%d", &i);

}

//Closing file

fclose (file);

printf("\nContents of the linklist:\n");

/*Display list*/

printList(head);

return 0;

}

/*For better understanding output screenshot and input file image are attached here*/

OUTPUT:

С:\Users\AmartyalDesktop\RumaC\FileReadInLL.exe Contents of the linklist: 11 2 34 21 99 19 3 42 28 46 7 91 Process exited after 0.02559 seconds with return value E Press any key to continue . - .

Input File:

inputData Notepad File Edit Format View Help 11 2 34 21 99 19 3 42 28 46 7 91

/*Hope this will help you.*/

/*If this helps you, please let me know by giving a positive thumbs up. In case you have any queries, do let me know. I will revert back to you. Thank you!!*/