Попытка реализации B*-tree(B-star tree) на Си

#include <stdio.h>
#include<stdlib.h>
#define N 4 
struct node {
    int key[N - 1];
    struct node* child[N];
    int isleaf;
    int n;
    struct node* parent;
};
struct node* searchforleaf(struct node* root, int k, 
                     struct node* parent, int chindex)
{
    if (root) {
        if (root->isleaf == 1)
            return root;
        else {
            int i;
            if (k < root->key[0])
                root = searchforleaf(root->child[0], k, root, 0);
                  
            else 
            {
                for (i = 0; i < root->n; i++)
                    if (root->key[i] > k)
                        root = searchforleaf(root->child[i], k, root, i);
                if (root->key[i - 1] < k)
                    root = searchforleaf(root->child[i], k, root, i);
            }
        }
    }
    else {
        struct node* newleaf = (struct node*)malloc(sizeof(struct node));
        newleaf->isleaf = 1;
        newleaf->n = 0;
        parent->child[chindex] = newleaf;
        newleaf->parent = parent;
        return newleaf;
    }
}
  
struct node* insert(struct node* root, int k)
{
    if (root) {
        struct node* p = searchforleaf(root, k, NULL, 0);
        struct node* q = NULL;
        int e = k;
        for (e = k; p; p = p->parent) { 
            if (p->n == 0) {
                p->key[0] = e;
                p->n = 1;
                return root;
            }
            if (p->n < N - 1) {
                int i,j;
                for (i = 0; i < p->n; i++) {
                    if (p->key[i] > e) {
                        for (j = p->n - 1; j >= i; j--)
                            p->key[j + 1] = p->key[j];
                        break;
                    }
                }
                p->key[i] = e;
                p->n = p->n + 1;
                return root;
            }
            if (p->n == N - 1 && p->parent && p->parent->n < N) {
                int m,i;
                for (i = 0; i < p->parent->n; i++)
                    if (p->parent->child[i] == p) {
                        m = i;
                        break;
                    }
                if (m + 1 <= N - 1) 
                {
                    q = p->parent->child[m + 1];
                      
                    if (q) {
                        if (q->n == N - 1) {
                            struct node* r = (struct node*)malloc(sizeof(struct node));
                            int* z = (int*)malloc(sizeof((2 * N) / 3));
                            int parent1, parent2;
                            int* marray = (int*)malloc(sizeof(2 * N));
                            int i;
                            for (i = 0; i < p->n; i++)
                                marray[i] = p->key[i];
                            int fege = i;
                            int j;
                            marray[i] = e;
                            marray[i + 1] = p->parent->key[m];
                            for ( j = i + 2; j < ((i + 2) + (q->n)); j++)
                                marray[j] = q->key[j - (i + 2)];
                            for ( i = 0; i < (2 * N - 2) / 3; i++)
                                p->key[i] = marray[i];
                            parent1 = marray[(2 * N - 2) / 3];
                            for ( j = ((2 * N - 2) / 3) + 1; j < (4 * N) / 3; j++)
                                q->key[j - ((2 * N - 2) / 3 + 1)] = marray[j];
                            parent2 = marray[(4 * N) / 3];
                            int f;
                            for ( f = ((4 * N) / 3 + 1); f < 2 * N; f++)
                                r->key[f - ((4 * N) / 3 + 1)] = marray[f];
                            if (m == 0 || m == 1) {
                                p->parent->key[0] = parent1;
                                p->parent->key[1] = parent2;
                                p->parent->child[0] = p;
                                p->parent->child[1] = q;
                                p->parent->child[2] = r;
                                return root;
                            }
  
                            else {
                                p->parent->key[m - 1] = parent1;
                                p->parent->key[m] = parent2;
                                p->parent->child[m - 1] = p;
                                p->parent->child[m] = q;
                                p->parent->child[m + 1] = r;
                                return root;
                            }
                        }
                    }
                    else 
                    {
                        int put;
                        if (m == 0 || m == 1)
                            put = p->parent->key[0];
                        else
                            put = p->parent->key[m - 1];
                            int j;
                        for ( j = (q->n) - 1; j >= 1; j--)
                            q->key[j + 1] = q->key[j];
                        q->key[0] = put;
                        p->parent->key[m == 0 ? m : m - 1] = p->key[p->n - 1];
                    }
                }
            }
        }
    }
    else 
    {
        struct node* root = (struct node*)malloc(sizeof(struct node));
        root->key[0] = k;
        root->isleaf = 1;
        root->n = 1;
        root->parent = NULL;
    }
}
int main()
{
    struct node* root = NULL;
    // Insert 6
    root = insert(root, 6);
    // Insert 1, 2, 4 to the left of 6
    root->child[0] = insert(root->child[0], 1);
    root->child[0] = insert(root->child[0], 2);
    root->child[0] = insert(root->child[0], 4);
    root->child[0]->parent = root;
      
      
    // Insert 7, 8, 9 to the right of 6
    root->child[1] = insert(root->child[1], 7);
    root->child[1] = insert(root->child[1], 8);
    root->child[1] = insert(root->child[1], 9);
    root->child[1]->parent = root;
      
      
     printf("Original tree: \n");
     int i;
    for ( i = 0; i < root->n; i++)
         printf(" %d ", root->key[i]) ;
    printf(" \n ");
    for ( i = 0; i < 2; i++) {
        printf(" %d ",root->child[i]->key[0]) ;
        printf(" %d ",root->child[i]->key[1]);
        printf(" %d ",root->child[i]->key[2]);
    }
    printf("\n");
      
      
    printf("After adding 5: \n" );
    root->child[0] = insert(root->child[0], 5);
    for (i = 0; i <= root->n; i++)
        printf(" %d ",root->key[i]);
    printf(" \n " );
    for (i = 0; i < N - 1; i++) {
        printf(" %d ",root->child[i]->key[0] );
        printf(" %d ",root->child[i]->key[1] );
    }
      
    return 0;
}

предполагаю что ошибка в функции insert.Программа работает, но ничего не выдаёт.