Software Design

Vending Machine Coin and Dispense Logic

State Diagrams · made in Skemio

State diagram showing vending machine operations: Idle to Accepting, Accepting to Checking Stock on item select, to Dispensing if in stock, to Returning Change, and back to Idle.
State diagram showing vending machine operations: Idle to Accepting, Accepting to Checking Stock on item select, to Dispensing if in stock, to Returning Change, and back to Idle.
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What it shows

  • Credit accumulation buffers continuous coin and note insertions.
  • Inventory checks guard dispense mechanisms against empty slots.
  • Change return loops calculate coin balance before returning to idle.

The takeaway

Validate stock before debiting balances to ensure atomic, trap-free transactions.

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