Targil 1- Vending Machine The problem   חברה רוצה לפתח מכונה אוטומטית למכירת שתייה (Vending Machine) לשוק בארה"ב. הציור המצורף, מתאר את נקודת המבט של הלקוח (Customer) לגבי המערכת. להלן תאור תכונות המערכת: 2005 Targil 1- Vending Machine

Targil 1- Vending Machine VM Characteristics Accept nickels, dimes and quarters from customers. Any other coins are to be treated as slugs and returned to the customer. Check each coin to make sure it is not a slug. This is to be done by validating the size and weight of each coin. Initiate payment computations only after detecting a valid coin. The system is to be difficult for people to trick. Accept product selection from the customer. Check to see whether the selected product is available in the dispenser. If not available, return coins and notify customer. A variety of products which will change from time to time shall be offered. The product prices should be changeable. Return the customer payment on request if he/she decides not to make a selection. Dispense the product if payment conditions are fulfilled and product is available. Return correct change to customer. Disable product selection after the product is dispensed and until the next validated coin is received. Make deposited coins available for change together with initial set of coins. 2005 Targil 1- Vending Machine

Targil 1- Vending Machine VM - Customer View 2005 Targil 1- Vending Machine

Targil 1- Vending Machine VM - Operator View 2005 Targil 1- Vending Machine

Targil 1- Vending Machine VM – Context diagram Objects Slugs Customer selection Returned coins Customer Customer Product Products in Vending Machine Coins in System Operator BIT information in Coins out Database information in Operator Database information out BIT status 2005 Targil 1- Vending Machine

VM – DFD-0 (Vending machine system) Product 1 Maintain Machine 2 Operator Customer Objects Customer selection Products in Coins in Database information in Slugs Returned coins Database information out Coins out BIT information in BIT status 2005 Targil 1- Vending Machine

VM – DFD-1 (Vend product) Get customer payments 1.1 Slugs Coins Inserted coins Extracted Dispense Change 1.2 Returned coins Validate payment 1.3 Payment Change due Products Price data Get product Price 1.4 Get valid selection 1.5 Customer selection product 1.6 Product data Valid selection Product Objects Price table 2005 Targil 1- Vending Machine

VM – DFD-1.1 (Get customer payment) 2005 Targil 1- Vending Machine

Targil 1- Vending Machine VM – PSPEC-1.1.1 – 1.1.5 Pspec 1.1.1: Validate coins Examine OBJECT to see if it matches any set of COIN PARAMETERS - If so: Accept OBJECT as COIN - Else: Return OBJECT as SLUG Pspec 1.1.2: Clear payment Issue PAYMENT = 0 Pspec 1.1.3: Accumulate payment Add COIN VALUE to PAYMENT Pspec 1.1.4: Accumulate coins Examine if HELD COINS .LE. HOLD CAPACITY then: - If so: Return COIN as SLUGS - Else: Add COIN to HELD COINS Pspec 1.1.5: Deposit coins Transfer HELD COINS to COINS 2005 Targil 1- Vending Machine

Targil 1- Vending Machine VM – Dictionary Sample Definition Term {Quarters, Dimes, Nickels} Coins {Soda, Candy, Gum, Cracker} Customer selection {Coins, Slugs} Objects Built-In-Test status results {OK, NOT-OK}, {Status} Status = {Computer, Keyboard, Display, Coins, Products, Mechanical} BIT status Display (reflect) “database information in” Database information out 2005 Targil 1- Vending Machine

Targil 1- Vending Machine The End 2005 Targil 1- Vending Machine