Class 15

Class 15 – Blockchain & Smart Contract Basics

Slides:Class15

In this lecture, we cover the core constructs of a contract in Solidity, focusing on enumerations, structures (structs), modifiers, and events.

1. Enumerations (Enums):
   • Enums in Solidity allow the creation of custom user-defined data types with a list of named constants.
   • Enums help in defining a set of predefined values, each assigned an integer starting from 0.
   • They can’t be declared within functions but can be used inside them, and they ensure cleaner and more readable code by reducing the use of arbitrary integers.
2. Structures (Structs):
   • Structs are composite data types that group multiple variables of different types under a single name.
   • Structs are used to represent a collection of data fields, such as an employee’s details.
   • They can contain arrays, enums, and mappings, but cannot contain functions.
3. Modifiers:
   • Modifiers are used to change the behavior of a function in Solidity.
   • They act like validation checks before executing the function’s logic.
   • Modifiers help in writing cleaner code by separating the validation logic from the main function code.
4. Events:
   • Events are used in Solidity to log certain activities or changes within a contract.
   • They notify external applications of contract state changes by emitting logs that are stored on the blockchain.
   • Events are accessible using the contract’s address but not within the contract itself.

These fundamental concepts are critical for developing efficient, readable, and secure smart contracts on the Ethereum blockchain.