A Problem with the index of an array of smart contracts in Solidity: Expected constant integer error

Question

I am totally new to solidity and not sure how different data types are used.

I am writing a code that handles an array of smart contracts, read and store values in them etc. In one function (storevalueincontract) I want to take an index (of an array consisting of smart contracts) and a value, and store that value via the function (store) in that contract. However, when I compile the code, I get the following error message:

TypeError: Integer constant expected.

referring to the following line:

simplestorage con = simplestorage[_index];

Here is the code:

// SPDX-License-Identifier: MIT

pragma solidity 0.8.8;

import "./simplestorage.sol";

contract Storage {

    simplestorage[] public cons;

function createsimplestorage() public{
    simplestorage cont=new simplestorage();

    cons.push(cont);
    }

function storevalueincontract(uint _index, uint _value) public{
simplestorage con = simplestorage[_index];
con.store(_value);
}


function viewvaluestoredinacontract(uint _index) public view returns(uint){
simplestorage con= simplestorage(simplestorage[_index]);
return con.retrieve();

}

Here is also the code for the smart contract named "simplestorage" in case it is needed:

// SPDX-License-Identifier: MIT
pragma solidity 0.8.8; // my first line in solidity

contract simplestorage{
    uint256 public favNum;
    people public father= people({favNum:2,name:"Faw"});
    people[] public family; 
    mapping(string => uint256) public name2FavNum;

    

    struct people{ //new type for people's name and favourite number
    uint256 favNum;
    string name;
    }

    function retrieve() public view returns(uint){
        return favNum;
    }

    function store(uint256 _favNum) public {
        favNum=_favNum;


    }

    function addperson(uint256 _num, string memory _name) public{
        people memory newperson = people({favNum:_num,name:_name});
        family.push(newperson);
        name2FavNum [_name]=_num;

    }




}

What could be the problem and how to solve it? I would appreciate any kind of help! thanks alot.

Answer 1

The array is named cons but you used simplestorage instead.

If you replace by the correct name it compiles.

function storevalueincontract(uint _index, uint _value) public{
    simplestorage con = cons[_index];
    con.store(_value);
}


function viewvaluestoredinacontract(uint _index) public view returns(uint){
    simplestorage con= simplestorage(cons[_index]);
    return con.retrieve();    
}