Problems creating linked list in while loop. Getting runtime error on second run in loop -


i writing program puts each line of text in node in linked list. want create new node each line in text. program crashes during second run in while loop. after testing think has strncpy-function, not sure. going wrong here?

#include <stdio.h> #include <stdlib.h> #define maxbuf 50  struct node {     char data[maxbuf];     struct node *next; };  int main(void) {     file *f;     f = fopen("text.txt", "r");     if (f == null) exit("error\n");      struct node *root = null;     struct node *pointer = null;      root = malloc(sizeof(struct node));     pointer = root;      char buf[maxbuf];     while(fgets(buf, maxbuf, f) != null)     {         strncpy(pointer->data, buf, maxbuf);         pointer->next = malloc(sizeof(struct node));         pointer->next = null;         pointer = pointer->next;     }     fclose(f); } 

pointer->next = null; pointer = pointer->next;

thus next time round loop:

while(fgets(buf, maxbuf, f) != null)     {         strncpy(pointer->data, buf, maxbuf);

pointer->data deference null. want test pointer null before strncpy , create malloc'd node there.

note never seem free of these nodes either.


Comments

Post a Comment

Popular posts from this blog

javascript - RequestAnimationFrame not working when exiting fullscreen switching space on Safari -

request animation frame stops working when exiting fullscreen clicking on original space's safari window. fine if fullscreen mode canceled escape key or calling cancelfullscreen(). steps reproduce: open https://dl.dropboxusercontent.com/u/769042/prezi/safari-fullscreen.html click "draw raf", kittie appears click "fullscreen", go fullscreen click "draw raf", kittie appears go space original safari was, showing "click exit fullscreen mode", click anywhere, out fullscreen click "draw raf", nothing happens what handling click calling: window.requestanimationframe(draw); which draws on canvas context: function draw() { ctx.drawimage(img, math.random()*500|0, math.random()*400|0, 100, 100); } i checked .hidden , .visibilitystate, updated correctly. tested on osx 10.9.3, safari 7.0.4 (9537.76.4). has workaround/solution other switching old settimeout? this sounds webkit bug 88940 : using reque...
Read more

jsf - How to ajax update an item in the footer of a PrimeFaces dataTable? -

this visual of table have: +---------+------------+-------------------+ | header1 | header2 | header3 | +---------+------------+-------------------+ | row | input | calc'ed output | | row b | input b | calc'ed output b | | etc.. | etc.. | etc.. | +---------+------------+-------------------+ | total: total calc'ed output | +------------------------------------------+ and stripped-down code: <p:datatable id="mytable" value="#{mybean.somelist}" var="currentitem"> <p:column headertext="header1"> <h:outputtext value="#{currentitem.name}" /> </p:column> <p:column headertext="header2"> <pe:inputnumber value="#{currentitem.inputval}"> <p:ajax event="change" listener="#{mybean.changelistener}" update="outputval outputtotal...
Read more

django - CSRF verification failed. Request aborted. CSRF cookie not set -

error: reason given failure: csrf cookie not set. in general, can occur when there genuine cross site request forgery, or when django's csrf mechanism has not been used correctly. post forms, need ensure: browser accepting cookies. view function uses requestcontext template, instead of context. in template, there {% csrf_token %} template tag inside each post form targets internal url. if not using csrfviewmiddleware, must use csrf_protect on views use csrf_token template tag, accept post data. you're seeing section of page because have debug = true in django settings file. change false, , initial error message displayed. can customize page using csrf_failure_view setting. did find, nothing helped, must foolish(( my template <form method="post">{% csrf_token %} {% field in form %} <div class="control-group"> {{ field }} </div> {% endfor %} <input type=...
Read more