Trie using c

Hi ,  I just tried out implementing trie  data structure using c , however my first attempt is not much memory efficient .

here is the code

#include<stdio.h>
#include<stdlib.h>
struct node
{
char data;
int final;
struct node *next[26];
};
struct node *insert(struct node *root,char *p)
{
if(root==NULL && *p!='\0')
{
int i;
struct node *temp = (struct node *)malloc(sizeof(struct node));
temp->data = *p;
 
for(i=0;i<26;i++)
{
temp->next[i] = NULL;
 
}
 
root = temp;
if(*(p+1)!='\0')
root->next[*p-97] = insert(root->next[*p-97],++p);
 
}
else if(*p!='\0')
{
if(root->data == *p)
root->next[*p-97] = insert(root->next[*p-97],++p);
else
root->next[*p-97] = insert(root->next[*p-97],p);
}
return root;
}
 
 
void traversal(struct node *root)
{
if(root!=NULL)
{
int i;
printf("%c",root->data);
for(i=0;i<26;i++)
{
traversal(root->next[i]);
 
}
 
}
 
}
  
int main()
{
char *p = "testing";
struct node *root = (struct node *)malloc(sizeof(struct node));
struct node *root1 = (struct node *)malloc(sizeof(struct node));
struct node *root2 = (struct node *)malloc(sizeof(struct node));
root=NULL;
root = insert(root," ");
 
root = insert(root,"apple");
root = insert(root,"ant");
root = insert(root,"body");
traversal(root);
 
}