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pragma solidity ^0.7.0; | |
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; | |
} | |
} | |
interface ERC20Interface { | |
function totalSupply() external returns (uint); | |
function balanceOf(address tokenOwner) external returns (uint balance); | |
function allowance(address tokenOwner, address spender) external returns (uint remaining); | |
function transfer(address to, uint tokens) external returns (bool success); | |
function approve(address spender, uint tokens) external returns (bool success); | |
function transferFrom(address from, address to, uint tokens) external returns (bool success); | |
event Transfer(address indexed from, address indexed to, uint tokens); | |
event Approval(address indexed tokenOwner, address indexed spender, uint tokens); | |
} | |
contract Ownership { | |
address public owner; | |
address public newOwner; | |
event OwnershipTransferred(address indexed _from, address indexed _to); | |
constructor() { | |
owner = msg.sender; | |
} | |
modifier onlyOwner { | |
require(msg.sender == owner); | |
_; | |
} | |
function transferOwnership(address _newOwner) public onlyOwner { | |
newOwner = _newOwner; | |
} | |
function acceptOwnership() public { | |
require(msg.sender == newOwner); | |
emit OwnershipTransferred(owner, newOwner); | |
owner = newOwner; | |
newOwner = address(0); | |
} | |
} | |
contract MyERC20Token is ERC20Interface, Ownership, SafeMath { | |
string public symbol; | |
string public name; | |
uint8 public decimals; | |
uint public _totalSupply; | |
mapping(address => uint) balances; | |
mapping(address => mapping(address => uint)) allowed; | |
constructor() { | |
symbol = "SKA"; | |
name = "SKA's Token"; | |
decimals = 18; | |
_totalSupply = 10000000000000000000000000; | |
} | |
function totalSupply() public override view returns (uint) { | |
return _totalSupply; | |
} | |
function balanceOf(address tokenOwner) public view override returns (uint balance) { | |
return balances[tokenOwner]; | |
} | |
function transfer(address to, uint tokens) public override returns (bool success) { | |
require(balances[msg.sender] >= tokens); | |
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 override 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 override returns (bool success) { | |
require(allowed[from][to] >= tokens); | |
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 override returns (uint remaining) { | |
return allowed[tokenOwner][spender]; | |
} | |
fallback () external payable { | |
revert(); | |
} | |
} |
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