Variables

There are 3 types of variables in Solidity

  • local
    • declared inside a function
    • not stored on the blockchain
  • state
    • declared outside a function
    • stored on the blockchain
  • global (provides information about the blockchain)
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.10;

contract Variables {
    // State varaibles are stored on the blockchain.
    string public text = "Hello";
    uint public num = 123;

    function doSomething() public {
        // Local variables are not saved to the blockchain.
        uint i = 456;

        // Here are some global variables
        uint timestamp = block.timestamp; // Current block timestamp
        address sender = msg.sender; // address of the caller
    }
}

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