library SafeMath { /** * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend). */ function sub(uint256 a, uint256 b) internal pure returns (uint256) { require(b <= a, "SafeMath: subtraction overflow"); uint256 c = a - b; return c; } /** * @dev Adds two unsigned integers, reverts on overflow. */ function add(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a + b; require(c >= a, "SafeMath: addition overflow"); return c; } }
/** * @title SafeMath * @dev Unsigned math operations with safety checks that revert on error. */
function sub(uint256 a, uint256 b) internal pure returns (uint256) { require(b <= a, "SafeMath: subtraction overflow"); uint256 c = a - b; return c; } /** * @dev Adds two unsigned integers, reverts on overflow. */ function add(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a + b; require(c >= a, "SafeMath: addition overflow"); return c; } }
/** * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend). */