jin10086

pragma solidity ^0.4.24;
library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    // Gas optimization: this is cheaper than asserting 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522

jin10086

pragma solidity ^0.4.23;

contract Ownable {
  address public owner;


  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );

jin10086

pragma solidity ^0.4.23;

contract Ownable {
  address public owner;


  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );

jin10086

pragma solidity ^0.4.23;

contract Ownable {
  address public owner;


  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );

jin10086

pragma solidity ^0.4.23;

contract Counter {
    uint private count = 0;

    function increment() public {
        count += 1;
    }

    function decrement() public {

jin10086

pragma solidity ^0.4.23;

contract Counter {
    uint private count = 0;

    function increment() public {
        count += 1;
    }

    function decrement() public {

jin10086

pragma solidity ^0.4.23;

contract Counter {
    uint private count = 0;

    function increment() public {
        count += 1;
    }

    function decrement() public {

jin10086

pragma solidity ^0.4.23;

contract Counter {
    uint private count = 0;

    function increment() public {
        count += 1;
    }

    function decrement() public {

jin10086

pragma solidity ^0.4.23;

contract Counter {
    uint private count = 0;

    function increment() public {
        count += 1;
    }

    function decrement() public {

jin10086

pragma solidity ^0.4.23;

contract Counter {
    uint private count = 0;

    function increment() public {
        count += 1;
    }

    function decrement() public {