Binary search tree and structure

Question

#include<stdio.h>
#include<stdlib.h>
struct node
{
    int data;
    struct node* left;
    struct node* right;
};


struct node(*new_node)(int);
struct node(*insert)(struct node*,int);
int search(struct node*, int);


int main()
{
    struct node* root;
    while(1)
    {
        int choice,data;
        printf("Enter Operation Choice To Perform\n1.Insert\n3.Search\n");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1: printf("Enter data");
                    scanf("%d",&data);
                    root=insert(root, data);
                    break;
            case 3: printf("Enter Data To Search\n");
                    scanf("%d",&data);
                    search(root,data);
                    break;
            case 5: exit(0);
                    break;
            default:printf("INVALID INPUT");
        }
    }

}
struct node(*new_node)(int data)
{
    struct node* new_node=(struct node*)malloc(sizeof(struct node));
    new_node->data=data;
    new_node->left=NULL;
    new_node->right=NULL;
    return new_node;
}
struct node (*insert)(struct node* root,int data)
{
    if(root==NULL)
        root=new_node(data);
    else if(data<=root->data)
        root->left=insert(root->left,data);
    else
        root->right=insert(root->right,data);
    return root;
}
int search(struct node* root, int data)
{
    if(root==NULL) return 0;
    else if(root->data==data) return 1;
    else if(data<=root->data) return search(root->left,data);
    else return search(root->right,data);
}

this is a basic insert and search for binary tree, can someone please help fix this code to get rid off the following error I can't seem to solve. --->incompatible types when assigning to type 'struct node *' from type 'struct node' --->expected '=', ',', ';', 'asm' or ' attribute ' before '{' token

Answer 1

With

struct node(*new_node)(int);

you declare the variable new_node , as a pointer to a function which takes one argument and returns a struct node .

What you want is to declare (and later define) the function as:

struct node*new_node(int);