pset5 : Speller: Trie: Segmentation Fault

Question

I have written a program on my linux computer, i wrote a program such that it takes user input to add a word to trie, and again user input to search in a trie, and it had worked perfectly!

But, when i converted it accordingly to speller requirements , i am getting a segmentation fault. Could someone help me with this?

/**
   * Implements a dictionary's functionality.
*/

 #include "dictionary.h"
 #include<stdio.h>
 #include<string.h>
 #include<stdlib.h>
 #include <stdbool.h>
 #include<ctype.h>

  struct trie
  {   
    bool flag;
    struct trie *tarr[27];
  };

   int free_word(struct trie *tnew);
   int add_word(char *a,struct trie *tnew);
   int l = 0,l1=0,l2 = 0,count=0;
    int se1_word(char *a,struct trie *tnew);

   struct trie tnew;

    /**
 * Returns true if word is in dictionary else false.
  */
   bool check(const char *word)
 {
   char dest[LENGTH+5];
   l2 = strlen(word);
   strcpy(dest,word);
   int a6 = se1_word(dest,&tnew);


   if ( a6 == 1)
   {
   return true;
   }
   else
  {
   return false;
  }
 }

     /**
 * Loads dictionary into memory. Returns true if successful else false.
 */
bool load(const char *dictionary)
{
    tnew.flag = false;
    int i;
    struct trie **dtrie = tnew.tarr;
    for(i=0;i<27;i++)
    {
    dtrie[i] = NULL;
    }

    FILE *fp = fopen(dictionary,"r");
    if ( fp == NULL)
    {
    return false;
    }
    char a[LENGTH+5];   
    while(fgets(a,LENGTH+1,fp) != NULL)
    {

    count += 1;
    l1 = 0;
    l = strlen(a);  
    add_word(a,&tnew);
    }
    fclose(fp);
    return true;
}

/**
 * Returns number of words in dictionary if loaded else 0 if not yet loaded.
 */
unsigned int size(void)
{
    if ( count != 0)
    {
    return count;
    }
    else
    {
    return 0;
    }
}

/**
 * Unloads dictionary from memory. Returns true if successful else false.
 */
bool unload(void)
{
    int k1 = free_word(&tnew);
    if ( k1 == 1)
   {
    return true;
   }
   else
    {
    return false;
    }
}

int se1_word(char *a,struct trie *tnew)
{
   //printf("add:%u\n",tnew); 
    l1 += 1;
    //printf("%s\n",a+l1);
    //printf("..l:%d,l1:%d\n",l,l1);
    //printf("tnew:%u\n",tnew);
    if ( tnew == NULL)           //for word of same size,but different words.
    {
        //printf("l1:%d,l2:%d\n",l1,l2); 
        return -1;
    }
    if ( l1 == l2)
    {
        if(tnew->flag == true)
        {
            return 1;
        }
        else
        {
            return -1;
        }
    }
        if ( a[l1] != '\'')
    {
        a[l1] = tolower(a[l1]);
    }
    int i1 = a[l1] - 'a';
    if ( a[l1] == '\'')
    {
      //  printf("haa\n");
        i1 = 26;
    }
    struct trie **arr = tnew->tarr;
    int k1 = se1_word(a,arr[i1]);
    return k1;
}

int free_word(struct trie *tnew)
{
    if ( tnew->flag == true)
    {
        return 1;
    }
    if ( tnew == NULL)
    {
        return 1;
    }
    int i =0;
    struct trie **array = tnew->tarr;
    for(i=0;i<27;i++)
    {
        if ( array[i] != NULL)
        {
            free_word(array[i]);
            free(array[i]);
        }
    }
    return 1;
}



int add_word(char *a,struct trie *tnew)
{
   printf("%s\n",a+l1);
   printf("l:%d,l1:%d\n",l,l1);
    //printf("add:%u\n",tnew);
    if ( l == l1)
    {

        tnew->flag = true;
        return 0;
    }
    if ( a[l1] != '\'')
    {
        a[l1] = tolower(a[l1]);
    }
    int a1 = a[l1] - 'a';
    if ( a[l1] == '\'')
    {

        //printf("haa\n");
        a1 = 26;
    }
    l1 += 1;
    struct trie **poi = (tnew)->tarr;
    struct trie **arr = poi;
    struct trie *new1  = calloc(1,sizeof(struct trie));
    struct trie **po2 = (new1->tarr);
    new1 ->flag = false;    
    int i1;

    for(i1=0;i1<27;i1++)
    {
        po2[i1] = NULL;
    }
    printf("add:%p\n",arr[a1]);  
   if(arr[a1] == NULL)
    {
    arr[a1] = new1;
    }
    int k1 = add_word(a,arr[a1]);
    return k1;
}

TIA!

Answer 1

Ok, guys, i understood where is the problem in my code. The problem was that fgets() actually adds a newline character at the end of the word. So the length of the string is increased by 1(if it was '\0' which would actually be at end of strings, the problem would not have occurred since it was '\n', strlen is increased by 1).

This was causing the problem. Fixed it.