Hash table is data structure to store or retrieve data in key value pair format. So it is like a table where key and value pertaining to that key exists . So, it is an efficient way of mapping and accessing data.

[key 1] -> Data 1
[key 2] -> Data 2
[key 3] -> Data 3

Hash table working:

• Hash Function - It is the function to search data in the hash table.
• Key Value Pair - The Key-Value pair is the primary thing of the hash table.
• Collisions - Collision is for that scenario when we have more than one key to store for a value.

void deleteEntry(char* state)
{
    int index = hashForKey(state);
    if (index < 0)
    {
        printf("Error deleting entry\n");
    }
    code[index] = 0;
}

void initHashTable ()
{
    int i;
    for (i = 0; i < TOTAL; i++)
        code[i] = 0;
}

int getCode( char *state)
{
    int index = hashForKey(state);
    if (index < 0)
    {
        printf("Error getting state code\n");
    }

    return code[index];
}

int main()
{
    char state[10][3] = {""};
    int codeNum[10];
    int i;
    int codeObtained = 0;

    for (i = 0; i < 10; i+=2)
    {
        printf ("Enter state (should be 2 chars in upper case)\n");
        scanf("%s", state[i]);

        printf ("Enter its code (integral - 3 numbers)\n");
        scanf("%d", &codeNum[i]);

        createEntry(state[i], codeNum[i]);
    }

    for (i = 9; i >=0; i--)
    {
        codeObtained = getCode(state[i]);
        printf("%s \t %d\n", state[i], codeObtained);
    }

    return 0;
}