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contracts...ExternalStorage.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity 0.8.18;

import "./1_Storage.sol";

interface IStorage {
    function store(uint256 num) external ;
    function retrieve() external view returns (uint256);
}

/**
 * Exemple d'interopérabilité des contrats.
 */
contract ExternalStorage {
    
    IStorage myStorage;
    
    function call(address _addr) public {
        myStorage= IStorage(_addr);
    } 

    function store(uint num) public {
        myStorage.store(num);
    }

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