CODEWITHSUNDEEP
clistsearchlinked-liststrcmp
keont
keont

Reputation: 673

Searching node in list both works and does not work

This might be a bad question but I'm completly lost. I have this code:

struct nodoTemas* search_in_list(char * val, struct nodoTemas **prev,struct nodoTemas *head/*, struct nodoTemas *curr*/)
{
struct nodoTemas *ptr = head;
struct nodoTemas *tmp = NULL;
bool found = false;

printf("\n Searching the list for value [%s] \n",val);

while(ptr != NULL)
{
    if(ptr->nombreTema == val)
    {
        found = true;
        break;
    }
    else
    {

        tmp = ptr;
        ptr = ptr->next;
    }
}

if(true == found)
{
    if(prev)
        *prev = tmp;
    return ptr;
}
else
{
    return NULL;//si no ha encontrado nada devuelve NULL
}

}

And I test it, in a specific file to test it, like this: 

char * var="tema1";
char * var2="tema2";
head=add_to_list(var,true,head,curr);
curr=head;
curr=add_to_list(var2,true,head,curr);
struct nodoTemas* nodoBuscado;
char *temaABuscar="tema4";
nodoBuscado=search_in_list(temaABuscar, NULL,head);

if(nodoBuscado!=NULL)
    printf("VALOR DEL NODO %s\n",nodoBuscado->nombreTema);

And it works perfectly fine no matter what I do. If I look for something that exists it prints it and so on. Now on my main file I get the char * my server gets the char * from a message. I thought this failed so I tried several things, this being one of them:

printf("MATCH %d \n" , strcmp(temaRecibido,head->nombreTema));

And I get a 0 as a result. So the strings are the same. But the search fails, in this other file. I've printed it, I've checked for their strlen sizes, and it all matches.

So I believe I'm looking at the wrong side but I cannot understand why code that is working in one place does not work in other. Should I look for the mistake somewhere else? Also, if I do strlen of a string WITH null and one without null, are they the same size? man says it excludes the terminating byte but I am unsure about this.

I'm sorry if the post is lacking I wasn't sure how to properly present it.

Upvotes: 0

Views: 47

Answers (2)

Madalosso
Madalosso

Reputation: 126

im not sure if you can compare strings in C that way... if you search for the string "tema1" instead a pointer to "tema1" what is the result? also, check this http://www.wikihow.com/Compare-Two-Strings-in-C-Programming.

Upvotes: 1

sray
sray

Reputation: 584

You cannot compare strings like 

if(ptr->nombreTema == val)

You should use strcmp

if(strcmp(ptr->nombreTema, val) == 0)

Upvotes: 1

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