以solidity 0.5.0返回字符串。函数中返回参数的数据位置必须是“内存”答案

【问题标题】：Return string in solidity 0.5.0. Data location must be "memory" for return parameter in function以solidity 0.5.0返回字符串。函数中返回参数的数据位置必须是“内存”
【发布时间】：2019-04-26 02:51:36
【问题描述】：

solidity编译器0.5.0版本如何返回字符串？

contract Test {
    string public text = 'show me';
    function  test() public view returns (string) {
        return text;
    }
}

我收到错误消息：

TypeError: Data location must be "memory" for return parameter in function, but none was given.

【问题讨论】：

标签： ethereum solidity smartcontracts

【解决方案1】：

//The version I have used is 0.5.2

pragma solidity ^0.5.2;

contract Inbox{


string public message;

//**Constructor** must be defined using “constructor” keyword

//**In version 0.5.0 or above** it is **mandatory to use “memory” keyword** so as to 
//**explicitly mention the data location**

//you are free to remove the keyword and try for yourself

 constructor (string memory initialMessage) public{
 message=initialMessage;
 }

 function setMessage(string memory newMessage)public{
 message=newMessage;

 }

 function getMessage()public view returns(string memory){
 return message;
 }}

【讨论】：

【解决方案2】：

只需要在string之后加上memory，像这样：

function test() public view returns (string memory) {

另一个变化： https://solidity.readthedocs.io/en/v0.5.0/050-breaking-changes.html#interoperability

【讨论】：