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int/uint：變長的有符號或無符號整型。變數支持的步長以8遞增，支持從uint8到uint256，以及int8到int256。需要注意的是，uint和int預設代表的是uint256和int256。
有符號整型能夠表示負數的代價是其能夠存儲正數的範圍的縮小，因為其約一半的數值範圍要用來表示負數。如：uint8的存儲範圍為0 ~ 255，而int8的範圍為-127 ~ 127
支持的運算符:
比較：<=，<，==，!=，>=，>，返回值為bool類型。
位運算符：&，|，（^異或），（~非）。
數學運算：+，-，一元運算+，*，/，（%求余），（**次方），（<<左移），（>>右移）。
小數由"."組成，在他的左邊或右邊至少要包含一個數字。如"1."，".1"，"1.3"均是有效的小數。
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Math {
function mul(int a, int b) public pure returns (int) {
int c = a * b;
return c;
}
function div(int a, int b) public pure returns (int) {
int c = a / b;
return c;
}
function sub(int a, int b) public pure returns (int) {
return a - b;
}
function add(int a, int b) public pure returns (int) {
int c = a + b;
return c;
}
}
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Math {
function m(int a, int b) public pure returns (int) {
int c = a % b;
return c;
}
}
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Math {
function m(uint a, uint b) public pure returns (uint) {
uint c = a**b;
return c;
}
}
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Math {
function yu() public pure returns (uint) {
uint a = 3; // 0b0011
uint b = 4; // 0b0100
uint c = a & b; // 0b0000
return c; // 0
}
function huo() public pure returns (uint) {
uint a = 3; // 0b0011
uint b = 4; // 0b0100
uint c = a | b; // 0b0111
return c; // 7
}
function fei() public pure returns (uint8) {
uint8 a = 3; // 0b00000011
uint8 c = ~a; // 0b11111100
return c; // 0
}
function yihuo() public pure returns (uint) {
uint a = 3; // 0b0011
uint b = 4; // 0b0100
uint c = a ^ b; // 0b0111
return c; // 252
}
}
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Math {
function leftShift() public pure returns (uint8) {
uint8 a = 8; // 0b00001000
uint8 c = a << 2; // 0b00100000
return c; // 32
}
function rightShift() public pure returns (uint8) {
uint8 a = 8; // 0b00001000
uint8 c = a >> 2; // 0b00000010
return c; // 2
}
}
a << n 表示a的二進制位向左移動n位，在保證位數沒有溢出的情況下等價于 a乘以2的n次方。
a >> n 表示a的二進制位向右移動n位，在保證位數沒有溢出的情況下等價于 a除以2的n次方。
string 字元串類型，字元串可以通過""或者''來定義字元串的值
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract StringTest {
string name;
function StringTest() public{
name = "default";
}
function setName(string _name) public{
name = _name;
}
function getName() public view returns(string){
return name;
}
}
在 Solidity 中想獲得字元串長度必須轉成 bytes 類型然後使用 length 屬性獲得。bytes(string).length
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract StringTest {
string public name = "http://www.netkiller.cn";
function nameBytes() public constant returns (bytes) {
return bytes(name);
}
function nameLength() public constant returns (uint) {
return bytes(name).length;
}
function length(string _name) public pure returns (uint) {
return bytes(_name).length;
}
}
![[提示]](../../../graphics/tip.png) | 提示 |
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注意：漢字採用UTF8編碼，一個漢字等於3個位元組，當你使用 length("景峯") 測試時會返回長度 6。 |
bool: 可能的取值為常量值true和false。支持的運算符：
! 邏輯非 && 邏輯與 || 邏輯或 == 等於 != 不等於 bool a = true; bool b = !a; // a == b -> false // a != b -> true // a || b -> true // a && b -> false
bytes names = "netkiller" bytes9 _names = "netkiller"; bytes(name)[0] = 0xFF; bytes memory _tmp = new bytes(3); _tmp[0] = 0x4e; _tmp[1] = 0x65; _tmp[2] = 0x6f;
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract BytesTest {
bytes names = "netkiller";
function get() public view returns (bytes) {
return names;
}
function getBytes2() public pure returns (bytes2) {
bytes9 _names = "netkiller";
return bytes2(_names);
}
function bytesToString() public constant returns (string) {
return string(names);
}
function copyBytes(bytes b) public pure returns (bytes) {
bytes memory tmp = new bytes(b.length);
for(uint i = 0; i < b.length; i++) {
tmp[i] = b[i];
}
return tmp;
}
function bytesToString2() public pure returns (string) {
bytes memory _tmp = new bytes(3);
_tmp[0] = 0x4e;
_tmp[1] = 0x65;
_tmp[2] = 0x6f;
return string(_tmp);
}
}
.length可以動態修改位元組數組的長度
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract BytesTest2 {
// 初始化一個兩個位元組空間的位元組數組
bytes public array = new bytes(2);
// 設置修改位元組數組的長度
function setLength(uint _len) public {
array.length = _len;
}
// 返回位元組數組的長度
function getLength() constant public returns (uint) {
return array.length;
}
// 往位元組數組中添加位元組
function pushArray(byte _tmp) public{
array.push(_tmp);
}
}
//創建一個memory的數組
uint[] memory a = new uint[](7);
uint[] x = [uint(1), 3, 4];
bytes memory b = new bytes(10);
二維數組
uint [2][3] T = [[1,2],[3,4],[5,6]];
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract ArrayTest {
uint [] array = [1,2,3,4,5];
// 通過for循環計算數組內部的值的總和
function sum() constant public returns (uint) {
uint num = 0;
for(uint i = 0; i < array.length; i++) {
num = num + array[i];
}
return num;
}
function sumNumbers(uint[] _numbers) public pure returns (uint) {
uint num = 0;
for(uint i = 0; i < _numbers.length; i++) {
num = num + _numbers[i];
}
return num;
}
}
.length 屬性是活動數組的尺寸
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract ArrayLength {
uint [] array = [1,2,3,4,5];
function getLength() public constant returns (uint) {
return array.length;
}
}
通過 push 可以向數組中添加數據
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract ArrayLength {
uint [] array = [1,2,3,4,5];
function pushArray() public {
array.push(6);
}
function getLength() public constant returns (uint) {
return array.length;
}
}
State 就是一個自定義的整型，當枚舉數不夠多時，它預設的類型為uint8，當枚舉數足夠多時，它會自動變成uint16，枚舉下標定義從左至右從零開始。
New=0, Pending=1, Done=2, Deleted=3
訪問枚舉方式 State.New 實際等於數字 0
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract EnumTest {
enum State { New, Pending, Done, Deleted }
State state = State.New;
function set(State _state) public {
state = _state;
}
function get() constant public returns (State) {
return state;
}
}
枚舉用來定義狀態
pragma solidity ^0.4.0;
contract Purchase {
enum State { Created, Locked, Inactive } // Enum
}
定義結構體
struct Voter {
uint weight; // weight is accumulated by delegation
bool voted; // if true, that person already voted
address delegate; // person delegated to
uint vote; // index of the voted proposal
}
// This is a type for a single proposal.
struct Proposal {
bytes32 name; // short name (up to 32 bytes)
uint voteCount; // number of accumulated votes
}
演示例子
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Students {
struct Person {
string name;
uint age;
uint class;
}
Person person = Person("Neo",18,1);
function getPerson() public view returns(string){
return person.name;
}
}
Struct 不知直接返回，解決方法如下
pragma solidity ^0.4.19;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract Netkiller {
struct JobStruct {
uint a;
uint b;
uint c;
}
function getValues () public pure returns (uint, uint, uint) {
JobStruct memory js = JobStruct(1, 2, 3);
return (js.a, js.b, js.c);
}
}
address public minter;
下面是一個獲得賬號餘額的例子。
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract AddressTest{
function getBalance(address _addr) public constant returns (uint){
return _addr.balance;
}
}
mapping 就是圖資料結構，由 key 和 value 組成。
pragma solidity ^0.4.25;
//Author: netkiller <netkiller@msn.com>
//Home: http://www.netkiller.cn
contract MappingExample {
mapping(uint => string) map;
function put(uint key, string value) public {
map[key] = value;
}
function get(uint key) constant public returns (string) {
return map[key];
}
}