CODEWITHSUNDEEP
cvariablessearchgetlinked-list
Rosolak
Rosolak

Reputation: 41

Searching for string in linked list and getting all variables

As I said i have problems with linked list.

#include <stdio.h>
#include <stdlib.h>

#define MAX 30

typedef struct elem{
    char name[MAX];
    int statistic;
    int price;
    struct elem *next;
    struct elem *prev;
}   shop;

I have function with search for word in a linked list and then i want to get all variables as tmpname,tmpstatistic and tmpprice in main and use them for other things.

void search(shop *first, char word[MAX], char tmpname[MAX], int tmpstatistic, int tmpprice)
{
    while (first!=NULL && strcmp(first->name, word) != 0)
    {
        first = first->next;
    }

    if (first != NULL && strcmp(first->name, word)==0)
    {
        printf("%s found! \n", word);
        printf("%s \n", first->name);
        printf("%d \n", first->statistic);
        printf("%d \n", first->price);
        tmpname=first->name;
        tmpstatistic=first->statistic;
        tmpprice=first->price;
    }
}

When i print them in function it works but when i want to print tmp ones in main they are wrong. If you could help me what to do to get good tmp variables in main. Im not really good at coding :/

Upvotes: 2

Views: 2252

Answers (2)

Rabbid76
Rabbid76

Reputation: 210909

You have to pass pointers to your function search to get values out. So you can set the result where the pointer refers to.

void search(shop *first, char word[MAX], char **tmpname, int* tmpstatistic, int* tmpprice)
                                           // ^             ^                  ^
{
    while (first!=NULL && strcmp(first->name, word) != 0)
    {
        first = first->next;
    }

    if (first != NULL && strcmp(first->name, word)==0)
    {
        printf("%s found! \n", word);
        printf("%s \n", first->name);
        printf("%d \n", first->statistic);
        printf("%d \n", first->price);
        *tmpname=first->name;           // assigne pointer to first->name where tmpname refers to
        *tmpstatistic=first->statistic; // assigne first->statistic where tmpstatistic refers to
        *tmpprice=first->price;         // assigne first->pricewhere tmppricerefers to
    }
}

If you need a copy of "name" use strcpy( *tmpname, first->name );

Call it like this:

search(first,word[MAX],&tmpname, &tmpstatistic, &tmpprice);

An other solution is to return a pointer to thefound element in list, or NULL if you didn`t find it:

shop* search(shop *first, char word[MAX])
{
    while (first!=NULL && strcmp(first->name, word) != 0)
    {
        first = first->next;
    }

    return first; // If you didn't find word in list, first is NULL, else first is the found elment
}

Upvotes: 2

Armen Tsirunyan
Armen Tsirunyan

Reputation: 132994

Well, your function takes the tmpname, tmpstatistic and tmpprice parameters by value. It means that essentially what you pass in main is copied and the copies are assigned meaningful values in your function but the variables you passed in main remain unchanged. Pass those parameters by pointer!

void search(shop *first, char word[MAX], char** tmpname, int* tmpstatistic, int* tmpprice)

And then use, for example, 

*tmpstatistic=first->statistic;

Upvotes: 3

Related Questions