CODEWITHSUNDEEP
cfilelinked-list
Adomas202
Adomas202

Reputation: 99

C read linked list from file and write to another file

I'm trying to make a program that would read a linked list and output all of the info that it has read. My problem is that I can't simply output. There is some problem that I can't find.

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


struct sarasas
{
    char *reiksme;
    struct sarasas *kitas;
};



int main()
{
    struct sarasas *sarasasPtr, *pradz, *pab, *elem;

    pradz = NULL;
    pab = NULL;

    FILE *duomPtr;
    printf("Iveskite duomenu failo pavadinima: ");
    char failas[255];
    scanf("%s", failas);
    duomPtr = fopen(failas, "r");

    if(duomPtr == NULL)
    {
        printf("Toks duomenu failas neegzistuoja \n");
        exit(0);
    }

    int k = 0;
    char paimtaReiksme[255];

    while(fscanf(duomPtr, "%s", paimtaReiksme) != EOF)
    {
        if(k == 0)
        {
            sarasasPtr = (struct sarasas*)malloc (sizeof (struct sarasas));
            sarasasPtr->reiksme = paimtaReiksme;
            sarasasPtr->kitas = NULL;
            pradz = sarasasPtr;
            pab = sarasasPtr;
        }

        else
        {
            sarasasPtr = (struct sarasas*)malloc (sizeof (struct sarasas));
            sarasasPtr->reiksme = paimtaReiksme;
            sarasasPtr->kitas = NULL;
            pab->kitas = sarasasPtr;
            pab = sarasasPtr;
        }
        k++;
    }

    if(pradz == NULL &&  pab == NULL)
    {
        printf("Tuscia\n");
        exit(0);
    }

    FILE *rptr;
    printf("Iveskite rezultatu failo pavadinima: ");
    char failas2[255];
    scanf("%s", failas2);
    rptr = fopen(failas2, "w");

    while(sarasasPtr->kitas != NULL)
    {
        fprintf(rptr, "%s", sarasasPtr->reiksme);
    }


    return 0;
}

Upvotes: 2

Views: 81

Answers (1)

Cherubim
Cherubim

Reputation: 5457

You have an infinite loop in your code.

while(sarasasPtr->kitas != NULL)
{
    fprintf(rptr, "%s", sarasasPtr->reiksme);
}

Here in the above while loop, you are trying to print the same element over and over again and thus you end up in an infinite loop.instead, you must change the pointer to next element after each and every iteration. You can try something like this:

while(sarasasPtr != NULL) //check whether pointer points to NULL
{
    fprintf(rptr, "%s", sarasasPtr->reiksme);
    sarasasPtr = sarasasPtr->kitas; //make pointer point to next element
}

additionally, you need not cast the the return value of malloc : Here's why(click)

Upvotes: 2

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