* list - displays all the cards in the rolodex, in alphabetical order from beginning to end.
* view - displays the card at the current position.
* flip - updates the current position to the next card, and displays it. Flipping past the last card wraps around to the first card.
* search - finds and displays a card, and makes it the current position in the rolodex. This command prompts for the last name for searching. If a matching card is found, it is displayed and is set as the current position. If no matching card is found, the card that immediately follows the lookup name is displayed and set as the current position (e.g. if "H" is entered as the last name, the first card with a last name following "H" in alphabetical order is displayed). If there is no following card, displays "Couldn't find: name"
* add - adds a new card to the rolodex. Prompts for each field value, reads it, and enters the new card in the correct position in the rolodex (based on alphabetical order). The new card is set as the current position.
* remove - removes the card at the current position. It displays the card and prompts for a confirmation for removal. The following card is set as the current position.
* modify - updates the card at the current position. Enters a mode that requests the field to be updated (e.g. phone #), displays the existing value and prompts for the new value, reads it, and updates the card. Continues prompting for additional changes until all changes are done (e.g. a 0 is entered for the field # to change). If the last name is changed, the card must be moved to the correct position in the rolodex (and is set as the current position).
* quit - exits the program.