Load File to Linked List – C

Program to load the integer data from file and add them at the end of singly linked list. The file named ‘numbers.txt’ will hold the integer numbers separated by space.

#include <stdio.h>
#include <stdlib.h>
struct node
{
    int data;
    struct node *next;
};
typedef struct node NODE;

NODE * insert_at_end(NODE * start, int data)
{
    NODE * newnode, * nextnode;
    newnode = (NODE *)malloc(sizeof(NODE));
    if(newnode == NULL) {
        printf("Memory Allocation Failed\n");
        return start;
    }
    newnode->data = data;
    newnode->next = NULL;

    if(start == NULL)
        start = newnode;
    else {
        nextnode = start;
        while(nextnode->next != NULL)
            nextnode = nextnode->next;
        nextnode->next = newnode;
    }
    return start;
}

void display(NODE * start)
{
    printf("The list read from file is...\n");
    while(start!=NULL) {
        printf("%d\t", start->data);
        start = start->next;
    }
}

int main()
{
    FILE *fp;
    int num;
    NODE *start = NULL;
    fp = fopen("numbers.txt", "r");
    if(fp == NULL) {
        printf("Unable to open file\n");
        return 0;
    }

    while(1) {
        if(feof(fp))
            break;

        fscanf(fp, "%d ", &num);
        start = insert_at_end(start, num);
    }
    fclose(fp);
    display(start);
    return 0;
}

 

Advertisements