Solidity Code Crowd Funding Project

//SPDX-License-Identifier: UNLICENSED

pragma solidity >=0.5.0 < 0.9.0;

contract CrowdFunding{

    mapping(address=>uint) public contributors; //contributors[msg.sender]=100

    address public manager; 

    uint public minimumContribution;

    uint public deadline;

    uint public target;

    uint public raisedAmount;

    uint public noOfContributors;

    struct Request{

        string description;

        address payable recipient;

        uint value;

        bool completed;

        uint noOfVoters;

        mapping(address=>bool) voters;

    }

    mapping(uint=>Request) public requests;

    uint public numRequests;

    constructor(uint _target,uint _deadline){

        target=_target;

        deadline=block.timestamp+_deadline; //10sec + 3600sec (60*60)

        minimumContribution=100 wei;

        manager=msg.sender;

    }

    function sendEth() public payable{

        require(block.timestamp < deadline,”Deadline has passed”);

        require(msg.value >=minimumContribution,”Minimum Contribution is not met”);

        if(contributors[msg.sender]==0){

            noOfContributors++;

        }

        contributors[msg.sender]+=msg.value;

        raisedAmount+=msg.value;

    }

    function getContractBalance() public view returns(uint){

        return address(this).balance;

    }

    function refund() public{

        require(block.timestamp>deadline && raisedAmount<target,”You are not eligible for refund”);

        require(contributors[msg.sender]>0);

        address payable user=payable(msg.sender);

        user.transfer(contributors[msg.sender]);

        contributors[msg.sender]=0;

    }

    modifier onlyManger(){

        require(msg.sender==manager,”Only manager can calll this function”);

        _;

    }

    function createRequests(string memory _description,address payable _recipient,uint _value) public onlyManger{

        Request storage newRequest = requests[numRequests];

        numRequests++;

        newRequest.description=_description;

        newRequest.recipient=_recipient;

        newRequest.value=_value;

        newRequest.completed=false;

        newRequest.noOfVoters=0;

    }

    function voteRequest(uint _requestNo) public{

        require(contributors[msg.sender]>0,”YOu must be contributor”);

        Request storage thisRequest=requests[_requestNo];

        require(thisRequest.voters[msg.sender]==false,”You have already voted”);

        thisRequest.voters[msg.sender]=true;

        thisRequest.noOfVoters++;

    }

    function makePayment(uint _requestNo) public onlyManger{

        require(raisedAmount>=target);

        Request storage thisRequest=requests[_requestNo];

        require(thisRequest.completed==false,”The request has been completed”);

        require(thisRequest.noOfVoters > noOfContributors/2,”Majority does not support”);

        thisRequest.recipient.transfer(thisRequest.value);

        thisRequest.completed=true;

    }

}