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SimpleStorage.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.7;

contract SimpleStorage{

    uint favoriteNumber;

    struct People{
        uint favoriteNumber;
        string name;
    }

    People[] public people; 

    mapping(string => uint) public nameToFavoriteNumber;

    function store(uint _favoriteNumber) public{
        favoriteNumber = _favoriteNumber;
    }

    //view and pure functions don't change the state of the smart contract.
    //They are only used to read state
    function retrieve() public view returns (uint){
        return favoriteNumber;
    }

    function addPerson(uint _favoriteNumber, string memory _name) public{
        people.push(People({favoriteNumber: _favoriteNumber, name: _name}));
        nameToFavoriteNumber[_name] = _favoriteNumber;
    }
}