Hashing -Linear probing

#include <stdio.h>
#include <stdlib.h>

#define HASH_TABLE_SIZE 10

int hash(int key) {
    return key % HASH_TABLE_SIZE;
}

int insert(int hashTable[], int key) {
    int index = hash(key);
    
    while (hashTable[index] != -1) {
        index = (index + 1) % HASH_TABLE_SIZE;
    }
    
    hashTable[index] = key;
    return index;
}

int search(int hashTable[], int key) {
    int index = hash(key);
    
    while (hashTable[index] != -1) {
        if (hashTable[index] == key) {
            return 1;
        }
        index = (index + 1) % HASH_TABLE_SIZE;
    }
    
    return 0;
}

void display(int hashTable[]) {
    int i=0;
    printf("Hash Table Contents:\n");
    for (i = 0; i < HASH_TABLE_SIZE; i++) {
        if (hashTable[i] != -1) {
            printf("Index %d: %d\n", i, hashTable[i]);
        } else {
            printf("Index %d: NULL\n", i);
        }
    }
}

int main() {
    int hashTable[HASH_TABLE_SIZE];
    int choice,key;
    int i;
    for (i = 0; i < HASH_TABLE_SIZE; i++) {
        hashTable[i] = -1; 
    }
while (choice!=4) {
	printf("\nChoose an operation:\n");
	printf("1. Display hash table\n");
	printf("2. Insert a key\n");
	printf("3. Search for a key\n");
	printf("4. Exit\n");

	scanf("%d", &choice);

	switch (choice) {
	    case 1:
		display(hashTable);
		break;
	    case 2:
		printf("Enter a key to insert: ");
		scanf("%d", &key);
		insert(hashTable, key);
		printf("Key inserted into the hash table.\n");
		break;
	    case 3:
		printf("Enter a key to search: ");
		scanf("%d", &key);
		if (search(hashTable, key)) {
		    printf("%d is found in the hash table.\n", key);
		} else {
		    printf("%d is not found in the hash table.\n", key);
		}
		break;
	    case 4:
		exit(0);
	    default:
		printf("Invalid choice. Please choose again.\n");
		break;
	}
    }
    return 0;
}