Thread: Transferring text from file into linked list

ok, im quite a bit furthur with this project but I have another problem *surprise*.

I have got my program to read the list in now, but I am trying to search it and it seems to start the list at the last word entered and then tries to access the one after it rather than the word entered before it.

I have included the code I have used below although there is quite a lot.

I get a segmentation fault in the searchlist function when trying to access the next item of the list. I think this is a fairly stupid mistake so hopefully something will jump out.

Thanks

Code:

char searchlist(list *root, char *word, int a, int b){
     
     if (root->thisnode[0] == '&'){
        return a;
     }
     else if(strcmp(word, root->thisnode) == 0){   
        a++;
        b++;
        searchlist(root->next, word, a, b);
     }
     else{
        a++;
        searchlist(root->next, word, a, b);
     }
     return 0;
}

list *insertlinkedlist(char *x){
     list *a;
     char y[50];
     int b;
     int c;
     int e;
     
     b = 0;
     e = 0;
     
     while (x[b] != '\0'){
           c = 0;
           
           while (x[b] != ' '){
                 y[c] = x[b];
                 b++;
                 c++;
           }     
           y[c] = '\0';

           a = insertlist(y, a);
           b++;
     }
     y[0] = '\0';
     a = insertlist(y,a);
     return a;
}

list *insertlist(char hd[50], list *a1){
     list *a;
     int b;
     int c;
     
     b = strlen(hd);
     a = calloc(1,sizeof(list));
     
     for (c = 0; c < b; c++){
         a->thisnode[c] = hd[c];
     }
     
     a->next = a1;
     return a;
     free (a);
}

int main(){
    char a[30];
    char b[50];
    char *y;
    list *z;
    int c;
    
    scanf("%s", a);
    y = readdata(a);
    printf("%s", y);
    z = insertlinkedlist(y);
    
    printf("\nEnter word for retrieval:");
    scanf("%s", b);
    c = searchlist(z,b,0,0);
    printf("%d", c);
    
    free(y);
    free(z);
    return 0;
}

well a is incremented in the program which then calls itself, so it shouldn't be 0 when the search gets to &, and the program would not compile without the return 0

also is it possible to return two values, as I need a and b to be returned to the main program or will I need to insert them both into an array.

the problem line is:
[code]
searchlist(root->next, word, a, b);
[\code]

as root->next seems to be set to an invalid memory address.

thanks for your help

when I debug it, it seg faults when it tries to re-call itself as the root->next address is invalid.

although I have changed the return now so it returns a instead of 0 but I have the same problem.

how would I solve this problem? because the way I have stored it isn't the last thing stored using the insertlist function the head of the list. As all the pieces of data are linked to the one added before it.

As it starts at last one entered shouldn't it seg fault when it reaches the first item inserted in the list?

I was messing about with the search function to see if there was anything wrong in it, and I found that the root->next is connected together correctly.

I used the following code to test whether hello would actually change to the next word in the list when it passes through the first time and it does. The memory address match up and all, so I can't really understand why it seg faults as I thought this only happens when trying to access a memory location that is unavaliable (which the first one isn't, even if the last one it would test would be).

Code:

char searchlist(list *root, char *word, int a, int b){
     list *hello;
     hello = root->next;
     if (root->thisnode[0] == '&'){
        return a;
     }
     else if(strcmp(word, root->thisnode) == 0){   
        a++;
        b++;
        return searchlist(hello, word, a, b);
     }
     else{
        a++;
        return searchlist(hello, word, a, b);
     }
     return a;
}

so this would be solved be inserting the calloc statement before the function is called rather than in the function?

i've changed that now but I still get the same problem, it has me baffled as the root->next node points to the correct memory address but it seg faults.