Please explain the idea of an array of contracts and the implementation of "sfStore" function

[kprabhasreddy]

// SPDX-License-Identifier: MIT 

pragma solidity ^0.8.7;

import "./SimpleStorage.sol"; 

contract StorageFactory {
    
    SimpleStorage[] public simpleStorageArray;
    
    function createSimpleStorageContract() public {
        SimpleStorage simpleStorage = new SimpleStorage();
        simpleStorageArray.push(simpleStorage);
    }
    
    function sfStore(uint256 _simpleStorageIndex, uint256 _simpleStorageNumber) public {
        // Address 
        // ABI 
        // SimpleStorage(address(simpleStorageArray[_simpleStorageIndex])).store(_simpleStorageNumber);

        



        // Do explain this line of code in brief
        simpleStorageArray[_simpleStorageIndex].store(_simpleStorageNumber); 
    }
    
    function sfGet(uint256 _simpleStorageIndex) public view returns (uint256) {
        // return SimpleStorage(address(simpleStorageArray[_simpleStorageIndex])).retrieve();
        return simpleStorageArray[_simpleStorageIndex].retrieve();
    }
}

[alymurtazamemon]

@kprabhasreddy What you did not understand?

[kprabhasreddy]

I could not breakdown what was happening when we are trying to add contracts to an array.

[pacelliv]

In this contract you wan to create as many SimpleStorage contracts you want, every time a new SimpleStorage is created it will be store in simpleStorageArray to be access whenever you want via its index.

The new contracts are added to simpleStorageArray using the push() method. This method allows you to add new elements to an array.

What happens if you have 5 SimpleStorage and you want to add numbers to them? sfStore takes two parameters: the index of a contract and the number to store, with these parameters you could add a number to any contract that is already stored in simpleStorageArray. This also apply to sfGet, if you pass an index to this function it will show you what number is stored in that contract.

[alymurtazamemon]

@kprabhasreddy @pacelliv has explained it well, let us know if you still have any queries.