What are the main components of a smart contract?

The main components include:

• State variables: Store data permanently on the blockchain
• Functions: Define contract behavior and interactions
• Events: Enable logging and external notifications
• Modifiers: Reusable code for function validation
• Constructor: Initializes contract state during deployment

contract Example {
    uint256 public value; // State variable
    
    constructor(uint256 _initialValue) { // Constructor
        value = _initialValue;
    }
    
    modifier onlyPositive(uint256 _value) { // Modifier
        require(_value > 0, "Value must be positive");
        _;
    }
    
    function setValue(uint256 _value) public onlyPositive(_value) { // Function
        value = _value;
        emit ValueChanged(_value); // Event
    }
    
    event ValueChanged(uint256 newValue); // Event
}