I have a ParserError here “function Stratus(string _greeting) {”

Question

pragma solidity ^0.4.19;

contract Stratus {

    string public greeting;
    address public owner;

    event GreetingChanged (string oldGreeting, string newGreeting)

    function Stratus(string _greeting) {
        greeting = _greeting;
        owner = msg.sender;
    }

    function setGreeting (string _greeting){
        require(owner == msg.sender)
        GreetingChanged(greeting,_greeting)
        greeting = _greeting
        }
    }

Answer 1

The version of solidity you are using is very old. The latest stable compiler for solidity is version:0.5.8+commit.23d335f2.Emscripten.clang. You can use the following code to remove the above error. But you have to use the latest version of solidity.

pragma solidity >=0.4.0 <0.6.0;

contract Stratus {

    string public greeting;
    address public owner;

    event GreetingChanged (string oldGreeting, string newGreeting);

    constructor(string memory _greeting) public {
        greeting = _greeting;
        owner = msg.sender;
    }

    function setGreeting (string memory _greeting) public {
        require(owner == msg.sender);
        emit GreetingChanged(greeting,_greeting);
        greeting = _greeting;
        }
    }

If you want to get ABI and Bytecode of above contract then you can get it by pasting the code in Remix.

But first, Change the compiler version in the remix to version:0.5.8+commit.23d335f2.Emscripten.clang

Use the older layout of remix if its showing new layout.

Changes I made:

1. I added newer version of solidity as pragma solidity >=0.4.0 <0.6.0;
2. I added semi-colon after some instructions
3. I added keyword public for the function, you can also make them private
4. I added keyword memory as if we are creating an array as a parameter of a function then we have to reserve memory for it first.
5. We have to use emit in latest solidity if we are calling a function which is not returning a value.

You can also check the syntax of latest stable version of the solidity.