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contracts...AddFiveStorage.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;
import {SimpleStorage} from "./SimpleStorage.sol";

contract AddFiveStorage is SimpleStorage {
    function sayBye() public pure returns (string memory) {
        return "Bye Ishu, Nice to meet you!";
    }

    // Overriding updateFavouriteNumber method
    function updateFavouriteNumber(uint256 number) public override {
        favouriteNumber = number + 5;
    }
}

contracts...SimpleStorage.sol

// SPDX-License-Identifier: MIT
/*
 * Specifying Solidity Compiler Version:
 * - `0.8.18`: Locks the compiler to this exact version (v0.8.18).
 *
 * - `^0.8.18`: Allows using this version or any newer minor/patch versions (e.g., 0.8.19, 0.8.20).
 *    Note: It will not include breaking changes from major versions like 0.9.0.
 *
 * - `>=0.8.0 <0.9.0`: Allows any version from 0.8.0 up to (but not including) 0.9.0.
 */
pragma solidity 0.8.24;

contract SimpleStorage {
    // If no access modifier is specified, the default visibility is `internal`.
    uint256 favouriteNumber;
    Person[] peopleList; // List of people with their favourite numbers
    mapping(string => uint256) nameToFavouriteNumber; // Maps a person's name to their favourite number

    struct Person {
        string name;
        uint256 favouriteNumber;
    }

    // virtual -> Allows this method to be overridden by derived (sub) contracts.
    function updateFavouriteNumber(uint256 _favouriteNumber) public virtual {
        favouriteNumber = _favouriteNumber;
    }

    // Returns the contract's favourite number (view -> read-only)
    function getFavouriteNumber() public view returns (uint256) {
        return favouriteNumber;
    }

    // Returns a fixed greeting message (pure -> does not read or modify contract state)
    function sayHello() public pure returns (string memory) {
        return "Hello, Ishu!";
    }

    /*
    * `memory`: Temporary variable that can be modified within the function.
    *
    * `calldata`: Temporary variable that cannot be modified within the function.
        It cannot be used as the function return type. Only valid for function input
        parameters.
    *
    * `storage`: Permanent variable that can be modified.
    */
    function addPerson(string memory _name, uint256 _favouriteNumber) public {
        peopleList.push(Person({name: _name, favouriteNumber: _favouriteNumber}));
        nameToFavouriteNumber[_name] = _favouriteNumber;
    }

    /*
     * `memory`: Used for the return type since the struct is temporarily loaded from storage.
     * Includes a check to prevent accessing an invalid index.
     */
    function getPersonAt(uint256 index) public view returns (Person memory) {
        require(index < peopleList.length, "Index out of bounds");
        return peopleList[index];
    }

    // If the name is not in the mapping, it returns 0 by default.
    function getFavouriteNumberByName(string memory _name) public view returns (uint256) {
        return nameToFavouriteNumber[_name];
    }
}

contracts...StorageFactory.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;
import {SimpleStorage} from "./SimpleStorage.sol";

contract StorageFactory {
    SimpleStorage[] public simpleStorageList;
    
    function createSimpleStorageContract() public {
        simpleStorageList.push(new SimpleStorage());
    }

    function sfUpdateFavouriteNumber(uint256 simpleStorageIndex, uint256 favouriteNumber) public {
        require(simpleStorageIndex < simpleStorageList.length, "Index Out of Bound");
        SimpleStorage currStorage = simpleStorageList[simpleStorageIndex];
        currStorage.updateFavouriteNumber(favouriteNumber);
    }

    function getFavouriteNumberOfStorage(uint256 index) public view returns (uint256) {
        return simpleStorageList[index].getFavouriteNumber();
    }
}