pragma solidity ^0.4.15;

library bigInt{
    struct bigint{
    int8 sign; //-1-"-" 1-"+"
    uint number;
    }
    // function bigIntcontract(uint8 _sign, uint _number) public{
    //     sign=_sign;
    //     number=_number;
    // }

    function fromUint (int8 _sign,uint _number) internal returns(bigint b){
        b.sign=_sign;
        b.number=_number;
        return b;
    }

    function show() internal  returns(bigint b){
        return(b);
    }

    function plus(bigint b1,bigint b2) internal returns(bigint b3){
        if (b1.sign==b2.sign){
            b3.sign=b1.sign;
            b3.number=b1.number+b2.number;
            return (b3);
        }
        if (b1.number>b2.number){
            b3.sign=b1.sign;
            b3.number=b1.number-b2.number;
            return (b3);
        }
        else{
            b3.sign=b2.sign;
            b3.number=b2.number-b1.number;
            return(b3);
        }
    }

    function minus(bigint b1,bigint b2) internal returns(bigint b3){
        b2.sign*=-1;
        b3=plus(b1,b2);
    }

    function mod(bigint b1, uint b2) internal returns(uint b3){
        b3=b1.number%b2;
        if(b1.sign==-1)
            b3=b2-b3;
        return(b3);
    }

    function multiply (bigint b1, bigint b2) internal returns(bigint b3){
        b3.sign=b1.sign*b2.sign;
        b3.number=b1.number*b2.number;
        return b3;
    }

    function multiply (bigint b1, uint b2) internal returns(bigint b3){
        b3.sign=b1.sign*1;
        b3.number=b1.number*b2;
        return b3;
    }

    function divide (bigint b1, bigint b2) internal returns(bigint b3){
        b3.sign=b1.sign*b2.sign;
        b3.number=b1.number/b2.number;
    }

    function divide (bigint b1, uint b2) internal returns(bigint b3){
        b3.sign=b1.sign*1;
        b3.number=b1.number/b2;
    }

}