you can instead use a factory class which creates token as follows in this design subtoken is an abstract class, implemented by token class and in the end a factory class which will create different instances of token class.

pragma solidity ^0.5.0; library SafeMath { function add(uint a, uint b) internal pure returns (uint c) { c = a + b; require(c >= a); } function sub(uint a, uint b) internal pure returns (uint c) { require(b <= a); c = a - b; } function mul(uint a, uint b) internal pure returns (uint c) { c = a * b; require(a == 0 || c / a == b); } function div(uint a, uint b) internal pure returns (uint c) { require(b > 0); c = a / b; } } contract SubToken{ 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 token is SubToken { mapping(address => uint) _balances; mapping(address => mapping(address => uint)) allowed; mapping(address => SubToken) public tokenlist; address[] public contracts; address owner = msg.sender; using SafeMath for uint; string public symbol; string public name; uint8 public decimals; uint _totalSupply; //constructor(string memory name,string memory symbol,uint8 decimals,uint256 _totalSupply) public{ // _balances[msg.sender]=_totalSupply; //} function totalSupply() public view returns (uint256) { return _totalSupply; } function balanceOf(address _owner) public view returns (uint256 balance) { return _balances[_owner]; } function transfer(address _to, uint256 _value) public returns (bool success) { return true; } function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) { emit Transfer(_from, _to, _value); return true; } function approve(address _spender, uint256 _value) public returns (bool success) { return true; } //function allowance(address _owner, address _spender) public view returns (uint256 remaining) { // return approve[_owner][_spender]; //} event Transfer(address indexed _from, address indexed _to, uint256 _value); event Approval(address indexed _owner, address indexed _spender, uint256 _value); } contract factory{ address[] public contracts; function createNewContract() public returns(address){ token st = new token(); contracts.push(address(st)); address(st); } }