Project1.sol

project1.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

/* states
    0 fundable
    1 completed
*/

contract FundingProject{
    enum State {Open, Closed}

    struct Project{
        string name;
        State state;
        address owner;
    }
    
    Project public project;

    constructor(string memory _name) {
      project = Project(_name, State.Open, msg.sender);
   }

   modifier isOwner(){
        require(msg.sender == project.owner,  "Only the owner can execute this");
        _;
   }

    function multiplicacion(uint a, uint b) external pure returns (uint product) { 
        return a*b; 
    }
    function getNumber() public pure returns (int number){
        number = 1984;
    }
    function changeNumber() public pure returns (int number){
        number = getNumber() *  -1;
    }
    function sendEther(address payable reciever) public payable{
        reciever.transfer(msg.value);
    }
    function getName() public view returns (string memory){
        return project.name;
    }

    event Funding(address sender, uint amount, uint total);

    function fundProject() public payable{
        require(project.state == State.Closed, "The project already closed");
        require(msg.value > 0, "Fund Value must be greater than 0");
        emit Funding(msg.sender, msg.value, address(this).balance);
    }

    function getBalance() public view returns (uint){
        return address(this).balance;
    }
    function closeProject() public isOwner{
        require(project.state == State.Closed, "The project is already closed");
        project.state = State.Closed;
    }

    function withdrawAllMoney() public isOwner{
        require(project.state != State.Closed, "Please close the project first");
        payable(project.owner).transfer(address(this).balance);
    }
}