The behavioral design patterns are used when a contract behaves differently according to its current state. In Solidity, we can have a contract in different states based on the values of its variables. These behaviors should be defined in the contract definition. According to the behavior defined in a contract, a contract transitions between different states. Let's look at some of the behavioral design patterns.
Behavioral patterns
State machine pattern
In a state machine, the initial state and the final state are known for the machine/process. Between these two states, there could be more intermediate states. In each state, different behaviors or functions are allowed on the machine. For example, a vending machine...