Here we introduce you to some primitive data types available in Solidity.

• boolean
• uint
• int
• address

// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;

contract Primitives {
    bool boo = true;

    /*
    uint stands for unsigned integer, meaning non negative integers
    different sizes are available
        uint8   ranges from 0 to 2 ** 8 - 1
        uint16  ranges from 0 to 2 ** 16 - 1
        ...
        uint256 ranges from 0 to 2 ** 256 - 1
    */
    uint8 u8 = 1;
    uint256 u256 = 456;
    uint u = 123; // uint is an alias for uint256

    /*
    Negative numbers are allowed for int types.
    Like uint, different ranges are available from uint8 to uint256
    */
    int8 i8 = -1;
    int256 i256 = 456;
    int i = -123; // int is same as int256

    address addr = 0xCA35b7d915458EF540aDe6068dFe2F44E8fa733c;

    // Default values
    // Unassigned variables have a default value
    bool defaultBoo; // false
    uint defaultUint; // 0
    int defaultInt; // 0
    address defaultAddr; // 0x0000000000000000000000000000000000000000
}