区块链基础

1.  以太坊部署完智能合约后，使用balanceOf函数会出现如下错误。

transact to ERC20Token.MyToken errored: Error: Returned error: invalid opcode: SHR

这种问题是创世区块引起的，可以使用如下genesis.json创建创世区块（相关链接：https://blog.ethereum.org/2019/02/22/ethereum-constantinople-st-petersburg-upgrade-announcement/）

{
  "config": {
    "chainId": 11,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "ethash": {}
  },
  "nonce": "0x0",
  "timestamp": "0x5d5cdc87",
  "extraData": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "gasLimit": "0x47b760",
  "difficulty": "0x80000",
  "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x0000000000000000000000000000000000000000",
  "alloc": {
    "0000000000000000000000000000000000000000": {
      "balance": "0x1"
    }
  },
  "number": "0x0",
  "gasUsed": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}