solidity data type

1. bool

   (기본연산 : !, &&, !!, ==, !=)

2. uint8/int8, uint16/int16, ~ uint32/int32, ~ uint64/int64, ~ uint128/int128,  ~ uint256/int256(uint/int)

   (기본연산

    비교 : <=, <, ==, !=, >=, >

    비트 연산 : &, |, ^, ~

    연산 : +, -, unary -, unary +, *, /, %, **, <<, >>

3. address (20 bytes) : 주소

   address owner = 0x023443423werwir342342kfwerkwr

   owner.balance : 잔고 (wei단위)

   owner.transfe : ether 보내기  (ex : owner.transfer(1 ether); , exception )

   owner.send : ether 보내기 (ex: owner.send(1 ether);, true/false)

   address productCont = 0x2334234152362626466464361

   productCont.call("getItem", "p1");  : low-level call

   productCont.call.gas(20000).value(1 ether).("getItem", "p2")

   msg.sender : 메시지/트랜잭션 보낸 주소

   msg.value

   msg.data

   msg.gas

   msg.sig

4. bytes1 ~ bytes32 (step 1)

   (<=, <, ==, !=, >=, >, & |, ^, ~, <<, >>)

5. string