huahuayu

0xa6D275A23Fd3ED513AA7E82b674960778ca6310C

huahuayu

pragma solidity ^0.4.21;

import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";

contract SafeMath {
    function safeToAdd(uint a, uint b) pure internal returns (bool) {
        return (a + b >= a);
    }
    function safeAdd(uint a, uint b) pure internal returns (uint) {
        require(safeToAdd(a, b));

huahuayu

1. solidity中除了uint外还有uint8,uint32,uint128,uint256等，那么uint默认是多少位的？
2. solidity中如何表示日期、时间？
3. 已知今天是20180513，要求23天后是哪一天？solidity中如何做到？
4. solidity中的now，取到的是一个什么时间？怎么转换为可读的日期+时分秒格式？
5. solidity是否支持uint --> string, string --> uint强制类型转换？如果要转换，如何转？
6. solidity中是否支持浮点数？如果要计算1.4 eth + 0.008 eth,如何做到？
7. solidity如何定义结构体？如何访问结构体中的元素？
8. mapping(address => uint) balances; 这个定义代表什么意思？
9. mapping(address => (uint => string)) vars; 这个定义代表什么意思？如何访问vars中的元素？
10. 数组uint[] numArrary = [1,7,2,4]; 如何访问第二个元素？如何添加元素（到末尾），如何删除元素（删除第二个元素，后面的元素前移），如何插入元素？

huahuayu

// Code generated - DO NOT EDIT.
// This file is a generated binding and any manual changes will be lost.

package main

import (
	"math/big"
	"strings"

	ethereum "github.com/ethereum/go-ethereum"

huahuayu

package main

import (
	"fmt"
	"log"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/ethclient"
)

huahuayu

package main

import (
	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/ethclient"
	"context"
	"fmt"
	"math/big"
	"github.com/ethereum/go-ethereum/accounts/abi"

huahuayu

package main

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"os/exec"
	"strings"
)

huahuayu

package unbuffered

import (
	"fmt"
	"net/http"
	"time"
)

func main() {
	links := []string{

huahuayu

package main

import (
	"gpool"
	"fmt"
	"net/http"
	"time"
)

func main() {

huahuayu

type CacheInterface interface {
  Get(key string) ([]byte, error)
  Set(key string, value interface{}) error
}

// Cache implements CacheInterface.
type Cache struct {
  // wrap redis pool connection
  // or whatever you need
}