Hash tables are not specific to C#. A hash table is a dynamic set data structure. It has three basic functions: to store data (SET/INSERT); to retrieve data (SEARCH/RETRIEVE), and to remove data that has previously been stored in the set (DELETE). In this way it is not different from other dynamic set data structure such as linked lists or trees. What is interesting about hash tables is their performance characteristics with respect to the store/retrieve/remove operations.
Understanding Dropshipping. Dropshipping is a retail fulfillment method where a store doesn't keep the products it sells in stock. Instead, when a store sells a product, it purchases the item from a third party and has it shipped directly to the customer. As a result, the merchant never sees or handles the product.
If you've been interested in starting your own internet business but you've been trying to avoid the hassles of things like developing and producing products, tracking your inventory, setting up warehouse space, and maintaining a confusing shipping/receiving infrastructure, then drop shipping may be your answer.