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contracts...Elementary Data Types...AddressType.sol

// SPDX-License-Identifier: GPL-3.0
 
pragma solidity >=0.7.0 <0.9.0;

contract AddressType {
    address public aDefaultAddress;

    // Example of a non checksum address (not allowed by solidity compiler)
    // Can fix using:
    // web3.utils.toChecksumAddress('0xecc6425db956125989c2c1a58a817bd90f86b3c0')
    // address public nonChecksumAddress = 0xecc6425db956125989c2c1a58a817bd90f86b3c0;

    // Same as above address but this time it is correctly checksumed
    // Details on EIP-55 here: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-55.md
    address public checksumAddress = 0xeCc6425dB956125989C2c1a58A817bD90f86B3C0;
}