ethereum(以太坊)(六)--整型(int)

/*
uint8 uint16 ...uint256
int8  int16 int24 ..int256

uint => uint256
int  =>  int256

int8 有符号 +1 ,-3
uint 无符号 1,2

int8 8(位)
1 111 1111 ~ 0 111 1111
- (1+2+4+8+16+32+64) ~ + (1+2+4+8+16+32+64)
-127 ~ 127  255（127*2+0）

uint8
0000 0000 ~ 1111 1111 (0~255)
*/

pragma solidity ^0.4.0;
contract Ballot {

    int8 _a;

    function set(int8 a){
        _a = a;
    }

    function get() constant returns(int8){
        return _a;
    }
}


pragma solidity ^0.4.0;
contract Ballot {

    function test1() constant returns(uint){
        uint8 a = 100;
        var b = a ;
        return b;
    }

    function test2() constant returns(uint){
        uint a;

        //var == uint8
        /*
        when i <= 255, i++ than i = 256,
        but max of uint8 is 255,so i cannot continue
        */
        for (uint i=0;i<=255;i++){
            a = i;
        }
        return a;
    }
}


pragma solidity ^0.4.0;
contract Ballot {
    uint8 a = 3;
    uint8 b = 7;
    //&, | ,^(异或),~(非)

    function yu() constant returns(uint){
        return a & b;
        //0000 0011
        //0000 0111
        //0000 0011 = 3  全1出1
    }

    function huo() constant returns(uint){
        return a | b;
        //0000 0011
        //0000 0111
        //0000 0111 = 7  有1出1
    }

    function yihuo() constant returns(uint){
        return a ^ b;
        //0000 0011
        //0000 0111
        //0000 0100 = 4 相同出0
    }

    function fei() constant returns(uint){
        return ~a;
        //0000 0011
        //1111 1100 = 255-3
    }
}

pragma solidity ^0.4.0;
contract Ballot {
    uint8 a = 7;
    uint8 b = 3;
    
    function add() constant returns(uint){
        return a + b;
    }
    function sub() constant returns(uint){
        return a - b;
    }
    function mul() constant returns(uint){
        return a * b;
    }
    function div() constant returns(uint){
        return a / b;
        //除(取整) 2
    }
    function mm() constant returns(uint){
        return a % b;
        //取余 1
    }
}

pragma solidity ^0.4.0;
contract Ballot {
    uint8 a = 3;
    //0000 0011
    
    function qiumi(uint8 b) constant returns(uint){
        return a ** b;
    }
    function leftShit(uint8 b) constant returns(uint){
        return a << b;
        //0000 0011 b=2 ->0000 1100 = 12
    }
    function rightShit(uint8 b) constant returns(uint){
        return a >> b;
        //0000 0011 b=2 ->0000 0000 = 0 
    }
}