HashTable

A hash table is a data structure that is used to store keys/value pairs. This particular hashtable is implemented using doubly linked list. It has total of 15 methods.

• insertFirst
• insertLast
• insertAtIndex
• getValueByIndex
• getValueByKey
• deleteFirst
• deleteLast
• deleteByVal
• deleteByIndex
• deleteByKey
• PrintkeyValues
• printValues
• printKeys
• PrintReverse
• length

insertFirst:

It takes two arguments key and value and stores them at the very begining of the table. If the key already exists, it replaces the current value of the key with the new value, without changing it's index.

insertLast:

It takes two arguments key and value and stores them at the very last index of the table. If the key already exists, it replaces the current value of the key with the new value, without changing it's index.

insertAtIndex:

It takes three arguments index, key and value and stores the value at the index provided by the user by shifting the reaming values 1 index ahead.It also checks for the key in the table. If the key already exists, it replaces it's current value with the new value without changing it's index.It also checks, if the index provided by the user is greater then the length of the table, it returns "Index not reachable".

getValueByIndex:

It takes one argument index and returns the value stored at the index.If the provided index is invalid it returns "index out of range".

getValueByKey:

It takes one argument key returns the value associated with the key.If the provided key is invalid, it returns "Key not found".

deleteFirst:

It deletes the first key/value pair stored in the table. It takes no arguments.

deleteLast:

It deletes the last key/value pair stored in the table. It takes no arguments.

deleteByVal:

It takes one argument value and deletes the first occurence of the provided value. if the value is not present in the table, it returns "Item not found".

deleteByIndex:

It takes one argument index and deletes the key/value pair at the provided index. If the provided index is invalid, it returns "Index not found".

deleteByKey:

It takes one argument key and deletes the key/value pair at the provided key. If the provided key is invalid, it returns "Key not found".

PrintkeyValues:

It prints the entire table in key/value pairs. It takes no argumnets.

printKeys:

It prints all the keys stored in the table. It takes no argumnets.

printValues:

It prints all the values stored in the table. It takes no argumnets.

PrintReverse:

It prints the entire table in reverse. It takes no argumnets.

length:

It returns the length of the table, i.e number of key/values pairs stored in the table. It takes no argumnets.