c - can't free memory correctly -

i'm working on pset6 of harvard's cs50 now, problem implement trie dictionary. managed make work small problem.

1. when run valgrind check memory leak, tells me i've freed 1 more i've allocated, can't see problem in unload function.
2. it warns me there uninitialized values, can't figure out although won't affect result.

here entire code:

/****************************************************************************  * dictionary.c  *  * computer science 50  * problem set 6  *  * valgrind warn there uninitialized values, node struct, don't  * know how initialize it, anyway, works @ last!  *   * implements dictionary's functionality.  ***************************************************************************/  #include <stdbool.h> #include <ctype.h>    #include "dictionary.h" #include <string.h> #include <stdio.h> #include <stdlib.h>  #define hashtable_size 5000  int count = 0;     // gloabal counter  typedef struct node {         // data structure      bool end_word;     struct node *children[27];     } node;  int charnumber(char c);   // function prototype  void  freenode(node *currentnode);  node root = {false,{null}}; /*  * returns true if word in dictionary else false.  */  bool check(const char *word) {     node *ptr = &root;     (int i=0;i<strlen(word);i++)     {         if (ptr->children[charnumber(word[i])] == null)             return false;         ptr = ptr->children[charnumber(word[i])];     }     if (ptr->end_word)         return true;     else         return false; }   /*  * loads dictionary memory.  returns true if successful else false.  */  bool load(const char *dictionary) { //    char word[length+1];  // must initialize zero! or there weird problem.     file *fp = fopen(dictionary,"r");     if (fp == null)         return false;     while (!feof(fp))     {         char word[length+1] = {};         fscanf(fp,"%s\n",word); // have use "%s\n" instead of "%s", or count wrong, don't know why.         count++;             node *ptr = &root;         (int i=0;i<strlen(word);i++)         {             if (ptr->children[charnumber(word[i])] == null)             {                 node *new = malloc(sizeof(node));                    *new = (node) {false,{null}};       // initiallization                 ptr->children[charnumber(word[i])] = new;                 ptr = new;             }             else             {                 ptr = ptr->children[charnumber(word[i])];             }          }          ptr->end_word = true;     } fclose(fp);            return true; }   /*  * caculate number character  */  int charnumber(char c) {     int num;     if (c == '\'')         return 26;     else if(c >= 'a' && c <= 'z')         c += 32;     num = c - 'a';     return num; }    /*  * returns number of words in dictionary if loaded else 0 if not yet loaded.  */  unsigned int size(void) {     if (count)         return count;     else         return 0; }   /*  * unloads dictionary memory.  returns true if successful else false.  */  bool unload(void) {     freenode(&root);     return true;         // can't figure out when return false... }  void freenode(node *currentnode) {     (int i=0;i<27;i++)     {         if (currentnode->children[i] != null)             freenode(currentnode->children[i]);     }     free(currentnode);  } 

here of valgrind output:

==22110== invalid free() / delete / delete[] ==22110==    @ 0x4024ecd: free (vg_replace_malloc.c:366) ==22110==    0x8048f90: freenode (dictionary_tries.c:152) ==22110==    0x8048f45: unload (dictionary_tries.c:141) ==22110==    0x8048ab5: main (speller.c:158) ==22110==  address 0x804a5a0 0 bytes inside data symbol "root" ==22110== --22110-- redir: 0x40b2930 (strchrnul) redirected 0x4028570 (strchrnul)   ==22110== ==22110== heap summary: ==22110==     in use @ exit: 0 bytes in 0 blocks ==22110==   total heap usage: 367,083 allocs, 367,084 frees, 41,113,776 bytes allocated ==22110== ==22110== heap blocks freed -- no leaks possible ==22110== ==22110== error summary: 1 errors 1 contexts (suppressed: 14 9) ==22110== ==22110== 1 errors in context 1 of 1: ==22110== invalid free() / delete / delete[] ==22110==    @ 0x4024ecd: free (vg_replace_malloc.c:366) ==22110==    0x8048f90: freenode (dictionary_tries.c:152) ==22110==    0x8048f45: unload (dictionary_tries.c:141) ==22110==    0x8048ab5: main (speller.c:158) ==22110==  address 0x804a5a0 0 bytes inside data symbol "root" ==22110== --22110-- --22110-- used_suppression:     14 u1004-arm-_dl_relocate_object ==22110== ==22110== error summary: 1 errors 1 contexts (suppressed: 14 9) 

suppose load function opens blank file. feof(fp) return 0, because read operation hasn't been used yet; eof flag set after read operation returns value indicating error. error lies. in case, need loop on return value of fscanf(fp,"%s\n",word); rather return value of feof. example:

while (fscanf(fp, "%s", word) == 1) {     /* ... */ }  if (feof(fp)) {     /* loop ended due eof */ } else if (ferror(fp)) {     /* loop ended due file input error */ } else {     /* loop ended because input invalid      * (this applies input conversion      *  required eg. conversion in %d, %u, %f, etc... */ } 

to elaborate, feof only determining why last read failed!

the reason cause such warning in case of blank file word contain indeterminate information.

additionally, freenode(&root); erroneous because free called on pointers returned calloc, realloc , malloc.