【開發智能合約 — Solidity系列】實作篇Ep.3 -資料型態的特性與流程控制

資料型態

Boolean

...
contract Example {    /// @dev 是否已經被檢查過
    bool private hasChecked = false;
}

Integer

...
contract Example {
    int256 private xInt256 = -100;
    // int256's alias
    int private xInt = -100;    // @dev uint無符號的整數型態
    uint8 private xUint8 = 128;
}

String

...
contract Example {
	 // correct
   string private str = "dynamic";	 // ParserError: Invalid character
	 string private str1 = "中文";
}

Address

• 僅收款的地址： address。
• 可付款的地址： address payable，不同之處在於多了「 transfer」跟「send」的功能。

address payable payableAddr = payable(0xdCad3a6d3569DF655070DEd06cb7A1b2Ccd1D3AF);
address addr = address(this);function assignAddress() public {
    // the balance of an address using the property 
    payableAddr.balance;
    // end Ether (in units of wei) to a payable address
    payableAddr.transfer(10);
}

流程控制

流程結構

// for...
uint count0 = 0;
// 累加10次的流程 
for (uint i = 0; i < 10; i++) {
	count0 += i;
}// 相當於上述的for ...
uint count1 = 0;
do {
	count1++;
} while(count1 < 10);/// @dev if ... else ...
bool isOpen = true;
string memory status = "";
if (isOpen) {
	status = "activated";
} else {
	status = "closed";
}

結語