Alex Phenom: Features of Solidity programming language

Solidity is the programming language used to create smart contracts within the Ethereum blockchain.

It’s a programming language that was designed to be easily picked up by those who are familiar with other languages. It has many similarities to the likes of Python or C, for example. Programming concepts that exist in other languages such as variables, functions, classes, and arithmetic operations, all exist here too. However, at present, there would appear to be a shortage of programmers who are highly familiar with Solidity, and how to use it.

When you consider how important smart contracts have been tipped to become in the future, it’s likely that programmers could make a lot of money by taking advantage of this gap in the job market.

After all, the demand for blockchain jobs is skyrocketing in the United States and overseas.

Below, we explore some of the basic features of Solidity and how they work.

What are the main data types in Solidity?

 Among Solidity’s data types are the well-known int, string, and bool, as well as the less familiar address and map. The address type will be a hex string of 40 characters, just as with all addresses on the Ethereum blockchain. This type of data creates value through the presence of attributes such as balance or methods like transfer. So, to send someone an Ether coin, you simply arrange a ‘transfer’ at the requested address. The map acts more like a dictionary where all possible keys, which values are initialized by zero-bytes.

All smart contract variables will either have a public or a private modifier, although it’s important to understand what ‘private’ really means. It might not necessarily be so private that no one can read its meaning. Although, blockchain is a decentralized database, it’s still true that all data within it is public. In this situation, ‘private’ modifier means solely that no single smart contract can read or modify this variable.

All Solidity coding takes place in the Ethereum database

All bytecode for smart contracts will be stored within the Ethereum blockchain. It is immutable, meaning it can’t be edited once it has been created. There are two functions: require and assert, which roll back all changes made and terminate the chain of execution. What’s more, there is a fallback function which triggers is a function signature doesn’t match any options in the Solidity contract.  Fallback functions are triggered when the function signature does not match any of the available functions in a Solidity contract. Alternatively, smart contracts can perform the self-destruct operation that removes the smart contract from the blockchain altogether. In doing so, the entire balance will be sent to the address account. In such a situation, the fallback function is not called.

A smart contract may contain a function that known as a constructor. This is responsible for ensuring an action occurring exactly at the time of a smart contract deploying. As such, this can be used to deploy global variables which will not need to be changed later on, (such as the owner of the contract for example).

It is important to understand where the address of the smart contract is taken. It is uniquely determined from the address of the creator and its number of the nonce (the number of completed transactions from this address), so do not assume that no one can know in advance the address of the contract and, for example, before the contract will be deployed to this address.

Is it worth learning Solidity?

In our opinion, these features are useful for developers who are just starting their way into the fascinating thorny world of Ethereum, the first platform that opened the doors to the world of smart contracts.

At present, learning Solidity from scratch is far from easy. There are a limited amount of books that have been published, and there appears to be not a single book with sterling reviews on Amazon.

However, if you’ve got the patience and dedication within you, it could be possible to teach yourself this language and open up a number of career opportunities as a result.


Alex Phenom


Alex Phenom is a blockchain enthusiast and founder of Phenom.Team – the fast-growing technology company with more than 20 members on board. At Phenom, Alex leads the research and development in the area of blockchain technology. Under his guidance Phenom.Team became a winner of two hackathons, developed more than 10 blockchain solutions and DAPPs and helped projects accomplish more than 10 ICOs with more than $50mln funds raised.

About the author: Andrew Beck