What are State Variables in Solidity?
State variables in Solidity are variables whose values are permanently stored in the contract's storage. Unlike local variables, which exist only during the execution of a function, state variables persist across function calls and transactions. They play a crucial role in maintaining the state of a smart contract.
When a smart contract is deployed on the Ethereum blockchain, its state variables are initialized and can be accessed and modified through functions defined in the contract. The data types of state variables can vary, including integers, strings, arrays, and user-defined types.
Each time a state variable is altered, the change is recorded on the blockchain, making the data immutable and transparent. For instance, in a token contract, state variables can include total supply or balances of each account, ensuring that the contract reflects the current state of those values.
Using appropriate visibility keywords for state variables, such as public,
private, or internal, allows developers to control their accessibility
and encapsulation, enhancing security and adhering to best practices in contract design.