IStudent.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.17;

struct Data{
        string name;
        uint Id;
        uint age;
        string gender;
        bool status;
    }

interface IStudent{
    function registerStudent(string calldata _name, address student, uint _age, string calldata _gender) external;

     function getStudent(address student) external view returns(Data memory _data);

     function studentsDetails() external view returns(Data[] memory list);

    function changeAdmin(address _newAdmin) external;

     function DeleteStudent(address student) external;
}

newChairman.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.17;


import {IStudent, Data} from "./IStudent.sol";

contract Chairman{

    address[] staffs;
    address Admin;  
    IStudent studentDetail; 


   constructor(address _studentDetails){
        Admin = msg.sender;
        studentDetail =IStudent( _studentDetails);
    }

    modifier onlyOwner(){
        require(msg.sender == Admin, "Not Admin");
        _;

    }


    function addStaff(address _staff) external onlyOwner{
        staffs.push(_staff);
    }

    function Register(string memory _name, address student, uint _age, string memory _gender) external {
        studentDetail.registerStudent(_name, student, _age, _gender);

    }


    function getStudent(address student) external view returns(Data memory _data) {
    studentDetail.getStudent(student);
    return _data;
}

    function studentsDetails() external view returns(Data[] memory list) {
        studentDetail.studentsDetails();
        return list;

    }

    function changeAdmin(address _newAdmin) external {
        studentDetail.changeAdmin(_newAdmin);
    }

    function DeleteStudent(address student) external {
        studentDetail.DeleteStudent(student);
    }

    fallback() external payable{}

    receive() external payable {}



}

student.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.17;




contract StudentDetails{
    struct Data{
        string name;
        uint Id;
        uint age;
        string gender;
        bool status;
    }
    mapping (address => Data) public data;
    Data[] public lists;
    address[] _studentState;

    address Admin;
    uint ID;



    constructor(){
        Admin = msg.sender;

    }

    modifier onlyOwner(){
        require(msg.sender == Admin, "Not Admin");
        _;

    }


    function registerStudent(string calldata _name, address student, uint _age, string calldata _gender) external onlyOwner{
        ID++;
        Data storage _data = data[student];
        require(_data.status == false, "Student already exist");
        _data.name = _name;
        _data.age = _age;
        _data.gender = _gender;
        _data.Id = ID;
        _data.status = true;
        _studentState.push(student);

       


    }


    function getStudent(address student) public view returns(Data memory _data){
        _data = data[student];
    }

    



    function studentsDetails() external view returns(Data[] memory list){
        uint size = _studentState.length;
        address[] memory  studentMemory = new address[](size);
        list = new Data[](size);
        studentMemory = _studentState;
        for(uint i =0; i < size; i++){
            Data storage _data = data[studentMemory[i]];
            list[i] = _data;
            list[i] =  data[studentMemory[i]]; 
        }

    }


    function DeleteStudent(address student) external onlyOwner{
        Data storage _data = data[student];
        require(_data.status == true, "Not student");
        _data.name = "";
        _data.age = 0;
        _data.Id =  0;
        _data.gender = "";
        _data.status = false;
        uint size = _studentState.length;
        address[] memory  studentMemory = new address[](size);
        studentMemory = _studentState;

        for (uint i = 0; i < size; i++){
            if(student == studentMemory[i]){
                studentMemory[i] = studentMemory[size - 1];
                _studentState = studentMemory;
                break;

            }
        }
        _studentState.pop();

    }


    function changeAdmin(address _newAdmin) external onlyOwner{
        Admin = _newAdmin;


    }




}