KPR-code-for-ICO/SafeMath.sol at master · KPRToken/KPR-code-for-ICO · GitHub

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pragma solidity^0.4.11;

/**
*@titleSafeMath
*@devMathoperationswithsafetychecksthatthrowonerror
*/
library SafeMath
{
    function mul(uint256 a, uint256 b) internal constant returns (uint256)
    {
        uint256 c=a*b;
        assert(a==0||c/a==b);
        return c;
    }
    function div(uint256 a,uint256 b) internal constant returns(uint256)
    {
        //assert(b>0);//Solidityautomaticallythrowswhendividingby0
        uint256 c=a/b;
        //assert(a==b*c+a%b);//Thereisnocaseinwhichthisdoesn'thold
        return c;
    }
    function sub(uint256 a,uint256 b) internal constant returns(uint256)
    {
        assert(b<=a);
        return a-b;
    }
    function add(uint256 a,uint256 b) internal constant returns(uint256)
    {
        uint256 c=a+b;
        assert(c>=a);
        return c;
    }
}