This is Day 12 of 30 in Solidity Series
Today I Learned About Enums in Solidity.

Enums are the way of creating user-defined data types, it is usually used to provide names for integral constants which makes the contract better for maintenance and reading.

Enums restrict the variable with one of a few predefined values, these values of the enumerated list are called enums. Options are represented with integer values starting from zero, a default value can also be given for the enum. By using enums it is possible to reduce the bugs in the code.

Syntax

enum <enumerator_name> { 
    element 1, 
    element 2,
    ....,
    element n
} 

Example:

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.7;

contract EnumType {
    // Creating an enumerator
    enum Days {
        Monday,
        Tuesday,
        Wednesday,
        Thursday,
        Friday,
        Saturday,
        Sunday
    }
    // Declaring variables of type enumerator
    Days day;

    // Setting a default value
    Days constant defaultDay = Days.Monday;

    // Get default Day
    function getDefaultDay() public pure returns (Days) {
        return defaultDay;
    }

    // Set day to a object from the enumerator Days
    function setDay() public {
        day = Days.Tuesday;
    }

    // get value of day
    function getDay() public view returns (Days) {
        return day;
    }
}

Output:

When we run the getDefaultDay function, we get the default value of the enumerator.

0:uint8: 0

When we run the getDay function we get 0:uint8: 0 as we have set it to a default value of Monday.

When we run the setDay function and then run the getDay function we get 0:uint8: 1 as setDay function has set the value of day to Tuesday.