Hash table

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;
#define MAX_TABLE 10
int arr_idx;
struct NODE {
	char data[7];
	NODE *prev;
} a[20000];
NODE *my_arr_alloc(void) {
	return &a[arr_idx++];
}
NODE *hTable[MAX_TABLE];
unsigned long myhash(const char *str) {
	unsigned long hash = 5381;
	int c;
	while (c = *str++) {
		hash = (((hash << 5) + hash) + c) % MAX_TABLE;
	}
	cout << "out:" << hash % MAX_TABLE<<endl;
	return hash % MAX_TABLE;
}
int main(void) {
	//freopen("input.txt", "r",stdin);
	//freopen("output.txt", "w", stdout);
	/*
	for(int i = 0; i < 100; i++) {
		for (int j = 0; j < 6; j++) {
			cout << (char)(rand() % 26 + 'a');
			cout << endl;
		}
	}
	*/
	//Initialize 
	arr_idx = 0;
	for (int i = 0; i < MAX_TABLE; i++) {
		hTable[i] = nullptr;
	}
	NODE *p;
	int key;//hash key int
	char in[7];
	int test_case;
	cin >> test_case;
	//Add char @Hash table 
	for (int t = 0; t < test_case; t++) {
		cin >> in;
		cout << "in:" << in<< endl ;
		key = (int)myhash(in);
		cout << "Add to Hash Table" << key << ":" << in << endl;
		p = my_arr_alloc();
		strncpy(p->data, in, 7);
		p->prev = hTable[key];
		hTable[key] = p;
		for (int _tKey = 0; _tKey < MAX_TABLE; _tKey++)
		{
			cout << "Hash table (" << _tKey << " ):";
			for (NODE *pp = hTable[_tKey]; pp != NULL; pp = pp->prev) {
				cout << "" << pp->data;
			}
			cout << endl;
		}
		cout << endl<<endl;
	}
	//Hash table search
	char search[7] = "vrvipy";
	cout << "Searching: " << search << endl;
	int k = (int)myhash(search);
	cout << "Hash table key: " << k << endl;
	// Search @Hash table [k]
	for (NODE *pp = hTable[k]; pp != NULL; pp = pp->prev) {
		if (!strncmp(search, pp->data, 6)) {
			cout << "Found:" << pp->data << endl<<endl;
		}
	}
}