【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