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 INVENTORY MANAGEMENT SYSTEM (OOP CAPSTONE) - Demo Run
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--- All products ---
  Wireless Mouse (SKU SKU001): 50 units @ $25.00 = $1250.00
  USB Cable (SKU SKU002): 5 units @ $8.00 = $40.00
  Coffee Beans (SKU SKU003): 30 units @ $12.00 = $360.00
  Expired Milk (SKU SKU004): 10 units @ $4.00 = $40.00 [EXPIRED]
  Software License (SKU SKU005): unlimited digital copies @ $49.99

--- Total inventory value ---
  $1690.00

--- Low stock report (threshold=10) ---
  USB Cable (SKU SKU002): 5 units @ $8.00 = $40.00

--- Sell/restock operations ---
  Sold 5x Wireless Mouse
  Cannot sell Expired Milk: expired
  Restocked USB Cable: +20 units
  Insufficient stock: only 45 available

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 Assignment: generate_inventory_report (polymorphic across all product types)
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=== INVENTORY REPORT ===
Total value: $1725.00

Low stock alerts (0):

Expired items (1):
  Expired Milk (SKU SKU004): 10 units @ $4.00 = $40.00 [EXPIRED]

Value by product type:
  Product: $1325.00
  PerishableProduct: $400.00
  DigitalProduct: $0.00
