How to compare struct with pointer

Question

I'm trying to compare a field of a struct that is holding a pointer of char with a pointer of char, but the comparison is not working.

typedef struct node{
    char * word;
    struct node * next;
    int occurrence;

}No;

           aux = list;
           while(aux != NULL){
            if(aux->word == token)
            {
                new_node->occurrence = new_node->occurrence+1;
                exist = 0;
            }
            aux = aux->next;
        }

We'll need a little bit more code than that. What is list? — Mark Benningfield
– Mark Benningfield, Commented Dec 12, 2017 at 17:25

user2736738 · Accepted Answer · 2017-12-12 17:28:16Z

2

if(aux->word == token)

Well you are comparing addresses and in the case they are equal (which is highly unlikely) it will enter the block.

Correct way to do is to check the contents. strcmp() is there to help you with that.

strcmp(aux->word, token) == 0

Compares the content pointed by them. That is appropriate here.

edited Dec 12, 2017 at 17:28

answered Dec 12, 2017 at 17:25

user2736738

31k5 gold badges45 silver badges57 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Paul Ogilvie Over a year ago

Well, it is posible that the adresses are the same. But indeed, he probably wants to know if the strings are the same.

user2736738 Over a year ago

@PaulOgilvie.: Not possible is too strong...But yes the OP wants to compare strings simply.

Nodarius · Accepted Answer · 2017-12-12 17:25:00Z

2

Instead of

if (aux->word == token) {
}

You need to write:

if (strcmp(aux->word, token) == 0) {
// your code here
}

man strcmp

answered Dec 12, 2017 at 17:25

Nodarius

2764 silver badges15 bronze badges

Comments

Shahrukh Shaikh · Accepted Answer · 2017-12-12 17:54:25Z

0

The == operator will not work with strings. The standard function strcmp() should be used. The function will return 0 if the strings are equal.

answered Dec 12, 2017 at 17:54

Shahrukh Shaikh

564 bronze badges

Collectives™ on Stack Overflow

How to compare struct with pointer

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related