BlockSurveyors

Team Name: Mind-Blockers

Team Members: Shuyi Wan, Yicong Yan, Madison Long, Jason Vu

Overview of the System:

The blockchain survey system is designed to enable users to create and participate in single-choice surveys, where each survey consists of a question with multiple integer-based options. The system includes functionalities for user registration, survey creation, participation, and automatic or manual survey closure with reward distribution.

Setup and Initialization Instruction

Check the README

APIs

• #

registerUser(string memory _username, uint256 _password) 

Call this function with your username and password to register. Only registered user can create a survey. Example: registerUser("username", 1234);

• Vote in a survey

vote(string memory _surveyName, uint256 option)

Vote for a certain survey using its name. Example:

vote("Survey 1", 1)  

---

• End the survey as the owner

endByOwner(string memory _surveyName)

End a certain survey using its name. Only the owner can do that, else return an error.

Example:

endByOwner("Survey 1");

---

• Create a survey

    function create_survey(
                          string memory _surveyName, 
                          string memory _question, 
                          string[] memory _solutions, 
                          uint256 _duration, 
                          uint256 _numAllowedResponses,
                          uint256 _password)

Create a survey by entering its required parameters. Example:

          string[] memory options = new string[](3);
          options[0] = "red";
          options[1] = "blue";
          options[2] = "green";
          create_survey{value: 1 ether}("Survey 1", "What is your favorite color?", options, 1, 4,1234);

---

• View a survey

    viewSurvey(string memory _surveyName) public returns 
    (string memory, string memory, string[] memory,uint256[] memory, uint256, uint256, uint256, uint256)

It gets all the information of the survey

        (
            string memory surveyName,
            string memory question,
            string[] memory surveyOptions,
            uint256[] memory answers,
            uint256 numAllowedResponses,
            uint256 startTime,
            uint256 endTime,
            uint256 ethReward
        ) = surveyContract.viewSurvey("Survey 1");

Private Functions

• End now

    endNow(string memory _surveyName) private noReentrancy

Ends the survey and send the reward to any participant, require the user to be the owner of the survey

endNow("surveyName");

---

• End Auto

    endAuto(string memory _surveyName) private noReentrancy

Ends the survey and send the reward to any participant, no requirement for user roles. Use when a survey is expired.

endAtuo("surveyName");

Components

• struct Survey, used to store the survey infomation
• struct registered_user, used to store user information
• modifier noReentrancy(), a modifier to prevent reentrancy
• mapping(string => Survey) private user_surveys, it's used to map a survey name to a survey
• mapping(string => uint256) private balances, keep track of the balance of each survey

Roles

• Register user: Can create a survey, can vote for any survey, can end the survey he creates
• Unregistered user: Can only vote for any survey