token.sol

contract SafeMath {
    function safeAdd(uint a, uint b) public pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function safeSub(uint a, uint b) public pure returns (uint c) {
        require(b <= a);
        c = a - b;
    }
    function safeMul(uint a, uint b) public pure returns (uint c) {
        c = a * b;
        require(a == 0 || c / a == b);
    }
    function safeDiv(uint a, uint b) public pure returns (uint c) {
        require(b > 0);
        c = a / b;
    }
}



contract ERC20Interface {
    function totalSupply() public view returns (uint);
    function balanceOf(address tokenOwner) public view returns (uint balance);
    function allowance(address tokenOwner, address spender) public view returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}



contract Owned {
    // address public owner;        <-- this is converted to the mapping of (address => bool)
    address public newOwner;
    mapping (address => bool) public owner;

    // event OwnershipTransferred(address indexed _from, address indexed _to);      <-- similarly instead of transferring ownership it is made "Owner added"
    event OwnerAdded(address indexed _which);

    constructor() public payable{
        // owner = msg.sender;          <-- previously it was user which is now converted to the set of owners by adding a bool value in front of one which is owner
        owner[msg.sender] = true;
        owner[0x14723A09ACff6D2A60DcdF7aA4AFf308FDDC160C] = true;
        owner[0x4B0897b0513fdC7C541B6d9D7E929C4e5364D2dB] = true;
        //owner[0x583031D1113aD414F02576BD6afaBfb302140225] = true;
    }

    modifier onlyOwner {
        require(owner[msg.sender]);
        _;
    }

    function transferOwnership(address _newOwner) public onlyOwner {
        newOwner = _newOwner;
    }
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerAdded(newOwner);
        // owner = newOwner;
        owner[newOwner] = true;
        newOwner = address(0);
    }
}



contract fuzz1Token is ERC20Interface, Owned, SafeMath {
    string public symbol;
    string public  name;
    uint8 public decimals;
    uint public _totalSupply;

    mapping(address => uint) balances;
    mapping(address => mapping(address => uint)) allowed;


    constructor() public payable {
        symbol = "FZT1";
        name = "FUZZ1 Token";
        decimals = 18;
        _totalSupply = 100000000000000000000000000;
        balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }


    function totalSupply() public view returns (uint) {
        return _totalSupply  - balances[address(0)];
    }


    function balanceOf(address tokenOwner) public view returns (uint balance) {
        return balances[tokenOwner];
    }


    function transfer(address to, uint tokens) public returns (bool success) {
        balances[msg.sender] = safeSub(balances[msg.sender], tokens);
        balances[to] = safeAdd(balances[to], tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }


    function approve(address spender, uint tokens) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        return true;
    }


    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
        balances[from] = safeSub(balances[from], tokens);
        allowed[from][msg.sender] = safeSub(allowed[from][msg.sender], tokens);
        balances[to] = safeAdd(balances[to], tokens);
        emit Transfer(from, to, tokens);
        return true;
    }


    function allowance(address tokenOwner, address spender) public view returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }


    function echidna_test() public returns(bool){
        if(balanceOf(0x4B0897b0513fdC7C541B6d9D7E929C4e5364D2dB) > 0)        
            return false;
        else return true;
    }


    function () external payable {
        revert();
    }
}