Solidity: Data location must be "memory" or "calldata" for return parameter in function

Question

I am learning Ethereum dev in solidity and trying to run a simple HelloWorld program but run into the following error:

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

Here is my code:

pragma solidity ^0.8.5;

contract HelloWorld {
  string private helloMessage = "Hello world";

  function getHelloMessage() public view returns (string){
    return helloMessage;
  }
}

Answer 1

You need to return string memory instead of string.

Example:

function getHelloMessage() public view returns (string memory) {
    return helloMessage;
}

The memory keyword is the variable data location.