The simplest ethereum smart contract

Creating smart contracts is easier than you think

Hi everyone! Today I want to speak about writign the simplest smart contract for ethereum blockchain.

So, idea of this article is about writing the simplest possible smart contract.

A bit of theory

I won’t talk too much about theory, you only need to know, that `Ethereum` is a global distributed virtual machine and you can run some code on it.

A bit of code

So, why don’t we write a simple `Hello World` program?

pragma solidity ^0.4.19;
 
contract HelloWorld {
    
    function sayHello() public view returns (string) {
        return "Hello, world!";
    }
    
}

We’ve done. That’s all. `contract` is some kind of classes for `Ethereum` (It’s not the absolute truth, but for the first step that explanation is ok).

A bit of code #2

For the second example we’ll create a contract with changing it’s state.

pragma solidity ^0.4.19;
contract Speaker {    
    string phrase;
function sayPhrase() public view returns (string) {
        return phrase;
    }
    
    function setName(string newPhrase) public {
        phrase = newPhrase;
    }
}

Here is it. In that contract we set `phrase` and can ask the contract to say it.
If we make phrase `public`, we will be able to read it’s state without `getter`.
But we still need the `setter`, because of `Ethereum` realisation’s features.

Conclusion

That’s all. I’ll be happy, If this article helps you