pragma solidity >=0.4.23 <0.6.0;
contract GlobalEntropy {
// Public variables of the token
using SafeMath for uint;
string public name;
string public symbol;
uint8 public decimals = 18;
uint256 public totalSupply;
// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);
// This generates a public event on the blockchain that will notify clients
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
/**
* Constructor function
*
* Initializes contract with initial supply tokens to the creator of the contract
*/
uint256 initialSupply = 3100000;
string tokenName = 'Global entropy';
string tokenSymbol = 'ETV';
constructor() public {
totalSupply = initialSupply * 10 ** uint256(decimals); // Update total supply with the decimal amount
balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
name = tokenName; // Set the name for display purposes
symbol = tokenSymbol; // Set the symbol for display purposes
}
/**
* Internal transfer, only can be called by this contract
*/
function _transfer(address _from, address _to, uint _value) internal {
require(_to != address(0));
require(balanceOf[_from] >= _value);
require(balanceOf[_to].add(_value) >= balanceOf[_to]);
uint previousBalances = balanceOf[_from].add(balanceOf[_to]);
balanceOf[_from]=balanceOf[_from].sub(_value);
balanceOf[_to]=balanceOf[_to].add(_value);
emit Transfer(_from, _to, _value);
require(balanceOf[_from].add(balanceOf[_to]) == previousBalances);
}
function transfer(address _to, uint256 _value) external returns (bool success) {
_transfer(msg.sender, _to, _value);
return true;
}
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
require(_value <= allowance[_from][msg.sender]); // Check allowance
allowance[_from][msg.sender].sub(_value);
_transfer(_from, _to, _value);
return true;
}
function approve(address _spender, uint256 _value) public
returns (bool success) {
allowance[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
}
library SafeMath {
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, errorMessage);
uint256 c = a / b;
return c;
}
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
{
"compilationTarget": {
"GlobalEntropy.sol": "GlobalEntropy"
},
"evmVersion": "byzantium",
"libraries": {},
"optimizer": {
"enabled": true,
"runs": 200
},
"remappings": []
}
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