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contracts...modifier.sol

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract modifiers{

    address public owner = msg.sender;
    uint public _xx = 10;

    //modifier is used to reuse the same code from the starting or ending of the function 
    modifier onlyOwner(){
        require(owner == msg.sender,"You are not the owner");
        _;  //this _; means that go back to that function from where modifier is called
    }
    modifier reuseCode(){
        for(uint i=0;i<10;i++){
            //code
        }
        _;
    }

    function startAuction() public onlyOwner {  //first call the modifier than function next code..
        //code
        //after this code execution go back to modifier again to check if further something actions on it 
        //if not than function ends
         _xx = _xx+10;

    }
    function stopAuction() public view onlyOwner{
        //code
    }
    function checkStatus() public view onlyOwner{
        //code
    }

    //calling input modifier example
    uint public age = 18;
    modifier checkAge(uint _x){
        age = age + _x;
        _;
    }
    function checkingAge(uint _y) public checkAge(_y){
        //next code after modifier calling
    }
}