How can I use struct parameter of a method to assign to another struct in C?

Question

I am trying to insert values from the binary search tree to linkedlist.

insertToLinkedList , I am using this method. But there is a problem with assigning.
struct node
struct nodeForLinkedList

struct node
{// Here node struct for leafs of the Tree
   
    char word[STRING_LEN]; //words
    struct node *left;
    struct node *right;
   
    
};
struct nodeForLinkedList
{
    
    char word[STRING_LEN]; //words
    struct node *left;
    struct node *right;
    struct node *next;
    
}
void insertToLinkedList(nodeForLinkedList *nodeL,char *data){
    struct nodeForLinkedList* new_node = (struct nodeForLinkedList*)malloc(sizeof(struct nodeForLinkedList)); 
    
     strcpy(new_node->word, data);                                       // To copy the elements of data to new node's word
    
    new_node->next = *nodeL; // Error occurs here.**(1)**
    *nodeL = new_node;// and here**(2)**


}

Errors:

no suitable conversion function from "nodeForLinkedList" to "node *" existsC/C++(413) (1)

no operator "=" matches these operands -- operand types are: nodeForLinkedList = nodeForLinkedList (2)

Those error messages are for C++, not C. – Barmar Dec 02 '20 at 22:59 — Barmar, Dec 02 '20 at 22:59

Barmar · Answer 1 · 2020-12-02T23:11:09.503

You need to change the declaration of nodeL to be a pointer to a pointer, so that you can update the caller's pointer variable.

void insertToLinkedList(nodeForLinkedList **nodeL,char *data){
    struct nodeForLinkedList* new_node = (struct nodeForLinkedList*)malloc(sizeof(struct nodeForLinkedList)); 
    
    strcpy(new_node->word, data);                                       // To copy the elements of data to new node's word
    
    new_node->next = *nodeL; // Error occurs here.**(1)**
    *nodeL = new_node;// and here**(2)**
}

And when you call the function, it should be

insertToLinkedList(&listVariable, stringVariable);

See Changing address contained by pointer using function for more information.

Thank u, this is quite helpful. – Mahmut Salman Dec 02 '20 at 23:10 — Mahmut Salman, Dec 02 '20 at 23:10

How can I use struct parameter of a method to assign to another struct in C?

1 Answers1