I have included the code for the contract below. The error I get when attempting to deploy in remix via metamask is:

> 
> Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? 
>  Error: gas required exceeds allowance or always failing transaction at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:1391377
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:927906
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:346093
>  at o
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:364324)
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:348923
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:346093
>  at c
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349199)
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349237
>  at Ht
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:358606)
>  at Object.
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349326)
>  at e.value
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:928821)
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:928388
>  at n
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:364268)
>  at o
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:364346)
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:348923
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:928354
>  at n
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:364268)
>  at o
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:364346)
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:348923
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:928727
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349733
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:346093
>  at c
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349199)
>  at s
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349121)
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:348923
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:349713
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:928609
>  at
>  chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:927046
>  at i
>  (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:1066207)
> 
> 
> 

Here is the contract code:

```
pragma solidity ^0.4.23;

library SafeMath {
//SafeMath library for preventing overflow when dealing with uint256 in solidity

  /**
* @dev Multiplies two numbers, throws on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
     if (a == 0) {
        return 0;
    }
    uint256 c = a * b;
    assert(c / a == b);
    return c;
}

/**
* @dev Integer division of two numbers, truncating the quotient.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
}

/**
* @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
}

/**
* @dev Adds two numbers, throws on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
}
}

contract ExampleToken {
using SafeMath for uint256;

string public constant name = "ExampleToken";
string public constant symbol = "EXT";
uint8 public constant decimals = 18; // 18 DECIMALS is the strongly suggested default, avoid changing it

//total supply (TOTALSUPPLY) is declared private and constant and can be accessed via totalSupply()
uint private constant TOTALSUPPLY = 200000000000 * (10**18);

// Balances for each account
mapping(address => uint256) balances;

// Owner of account approves the transfer of an amount to another account
//This is a mapping of a mapping
// This mapping keeps track of the allowances given
mapping(address => mapping (address => uint256)) allowed;

//Constructor
constructor () public {

    //sends all the tokens to the address of the contract creator
    balances[msg.sender] = TOTALSUPPLY;

    emit Transfer(address(0), msg.sender, TOTALSUPPLY);
}

             //*** ERC20 FUNCTIONS ***//
//1
/**
* @dev total number of tokens in existence
*/
function totalSupply() public pure returns (uint256 _totalSupply) {
    //set the named return variable as the global variable TOTALSUPPLY
    _totalSupply = TOTALSUPPLY;
}

//2
/**
* @dev Gets the balance of the specified address.
* @param _owner The address to query the the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function balanceOf(address _owner) public view returns (uint256 balance) {
    return balances[_owner];
}

//3
/**
* @dev transfer token for a specified address
* @param _to The address to transfer to.
* @param _value The amount to be transferred.
*/
//Note: returns a boolean indicating whether transfer was successful
function transfer(address _to, uint256 _value) public returns (bool success) {
    require(_to != address(0)); //not sending to burn address
    require(_value <= balances[msg.sender]); // If the sender has sufficient funds to send
    require(_value>0);// and the amount is not zero or negative

    // SafeMath.sub will throw if there is not enough balance.
    balances[msg.sender] = balances[msg.sender].sub(_value); // subtract from sender
    balances[_to] = balances[_to].add(_value); // add same to recipient
    emit Transfer(msg.sender, _to, _value);
    return true;
}

//4
//Owner "approves" the given address to withdraw instances of the tokens from the owners address
/**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   *
   * Beware that changing an allowance with this method brings the risk that someone may use both the old
   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
}

//5
//Lets an "approved" address transfer the approved amount from the address that called approve()
/**
 * @dev Transfer tokens from one address to another
 * @param _from address The address which you want to send tokens from
 * @param _to address The address which you want to transfer to
 * @param _value uint256 the amount of tokens to be transferred
 */
function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
}

//6
/**
 * @dev Function to check the amount of tokens that an owner allowed to a spender.
 * @param _owner address The address which owns the funds.
 * @param _spender address The address which will spend the funds.
 * @return A uint256 specifying the amount of tokens still available for the spender.
 */
function allowance(address _owner, address _spender) public view returns (uint256) {
    return allowed[_owner][_spender];
}

//additional functions for altering allowances
/**
 * @dev Increase the amount of tokens that an owner allowed to a spender.
 *
 * approve should be called when allowed[_spender] == 0. To increment
 * allowed value is better to use this function to avoid 2 calls (and wait until
 * the first transaction is mined)
 * From MonolithDAO Token.sol
 * @param _spender The address which will spend the funds.
 * @param _addedValue The amount of tokens to increase the allowance by.
 */
function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
}

/**
 * @dev Decrease the amount of tokens that an owner allowed to a spender.
 *
 * approve should be called when allowed[_spender] == 0. To decrement
 * allowed value is better to use this function to avoid 2 calls (and wait until
 * the first transaction is mined)
 * From MonolithDAO Token.sol
 * @param _spender The address which will spend the funds.
 * @param _subtractedValue The amount of tokens to decrease the allowance by.
 */
function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
    uint oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue > oldValue) {
        allowed[msg.sender][_spender] = 0;
    } else {
        allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
}

          //***ERC20 Events***//
//Event 1
// Triggered whenever approve(address _spender, uint256 _value) is called.
event Approval(address indexed _owner, address indexed _spender, uint256 _value);

//Event 2
// Triggered when tokens are transferred.
event Transfer(address indexed _from, address indexed _to, uint256 _value);

}

```

I appreciate any help. I have tried setting maximum gas limit and gas prices but the contract won't deploy. I have the same problem when attempting to deply it using bytecode on MEW.