Solidity is a simple programming language designed to create smart contracts on the Ethereum network. The newly constructed language has played a significant role in Ethereum’s contracts architecture, which is critical in blockchain technology; learning the language will be essential if you want to code Ethereum Dapps (Decentralized Applications).
This language was established to demonstrate the true capabilities of the smart contract system in digital transactions.
This quick guide is a review for individuals who haven’t worked with smart contracts in a long time or for newcomers who wish to grasp the fundamentals of Solidity smart contracts. Let’s get started.
What is Solidity?
Solidity is a programming language for writing smart contracts. Gavin Wood and Christian Reitwiessner developed it in the context of the Ethereum project.
Solidity is a statically typed, contract-oriented programming language for writing smart contracts that can be compiled to bytecode and EVM (Ethereum Virtual Machine) bytecode for execution on Ethereum’s blockchain. Solidity is designed to target the needs of the average programmer, not programmers familiar with formal languages such as Java, C++, or Ada.
Moreover, Solidity was designed to detect common programming errors at compile-time, such as insufficient gas or incorrect mapping initialization. As a result, some errors in Solidity programs do not
become apparent until runtime; nevertheless, compilers can generally still provide helpful information about them.
The language also supports state variables (equivalent to objects in Object-Oriented Programming), data types, and programming functions. On the other hand, the language is subject to frequent upgrades and modifications across the platform. As a result, you must monitor Ethereum platform forums, websites, and chat sessions for improvements as a programmer.
Need of Smart Contracts
Smart contracts are helpful digital tools for transferring ownership and conditional fulfillment. Mutual trust, transparency, global communication, and economics are all addressed. Here are a few examples of smart contract applications in the real world.
Smart contracts allow the performance of credible transactions without third parties. These transactions are trackable and irreversible.
The most common application of smart contracts today is as part of a blockchain-based cryptocurrency system. In this case, the terms of the contract are written in code as part of the blockchain system. When one party sends money (for example, in bitcoin) to another party, that transfer is recorded on the blockchain ledger and becomes unalterable.
Functionalities of Solidity
Solidity provides a high level of security while still being easy to understand and write. Let’s discuss some of its functionalities.
Mapping
Mapping is a Solidity data structure that stores key-value pairs. It has two primary operations: get and set. The get operation takes the key as an input and returns the corresponding value, while the set operation takes both the key and the value as inputs, sets the corresponding entry in the mapping to this new value, and returns true if successful or false.
The concept of Mapping in Solidity is straightforward but can be challenging to understand at first glance. To make it easier for people to grasp, we will start from a basic example of how one would use mapping to store information about their contacts.
Mapping Example
// mapping(_KeyType => _ValueType) mapping(address => uint) public balances; // Setting a new map balances[msg.sender] = newBalance;
Mapping Features
- There is no concept of a key or a value being set in mappings, neither do they have a length.
- Only state variables that serve as store reference types can be mapped.
- When mappings are created, they contain every possible key and are mapped to values with byte-representations that are all zeros.
Modifiers
In a smart contract, function modifiers are used to adjust or limit the functionality of a function. A modifier can be used to assess various conditions before executing a function.
For example, before accomplishing a task, you can check an account’s balance, confirm the sender is the owner, request authorization to an account, and so on. Modifiers are customizable code blocks that can be applied to a single or several functions in your program.
Example of Modifiers
// The onlyOwner modifier
modifier onlyOwner {
require(msg.sender == owner);
_;
}
// Call a function a modifier
function register() public payable costs(price) {
//...
}
Features of Modifiers
The features of modifiers in Solidity are the following:
- Modifiers can be used to modify the state of a contract.
- Modifiers are also called “assertions,” which are functions that are only executed when certain conditions have been met.
- They can be used to guard against unwanted behavior and bugs in contracts.
- They cannot change the contract’s state more than once.
- The modifiers should always be executed in steps, meaning that they should not execute any other code before executing all their code and then modifying the state of the contract.
Functions
In the Solidity programming language, functions are special. They are used to define a set of instructions for the Ethereum Virtual Machine (EVM) to execute.
Functions can be classified as either external or internal. External functions can be invoked by other contracts and transactions, whereas internal functions cannot be invoked from outside the contract in which they are defined.
A function should have a clear purpose that will make it easier to identify its use cases and understand its input/output parameters. This will make it more maintainable and easier to follow when reading through code.
Example of Functions
// Example of a simple function
function getResult() public view returns(uint){
uint x = 1;
uint y = 2;
uint result = x + y;
return result;
}
Features of Functions
The following are some of the features of functions in Solidity:
- Functions can return values
- Functions can take any number of arguments
- Functions have an explicit return type declaration
- Functions have a stateless default function (constructor)
- Function arguments are passed by value
Variables in Solidity
Variables in Solidity are classified as either state variables or local variables.
State Variables
A state variable is a variable that can change from one value to another and is stored in the blockchain. The state variables are initialized at the contract creation time.
The state variables are stored on the blockchain as follows:
- The address of a contract is its unique identifier on the blockchain. It represents a contract’s location in the Ethereum network.
- The data about a contract’s storage, including any current values of its state variables, is stored in the blockchain as transactions that update those values.
- State variables are public and can be accessed by anyone with an Ethereum client or by querying an Ethereum node directly.
Local Variables
A local variable is a variable that is declared and initialized within a function. The variable’s scope is limited to the function in which it was declared.
Local variables are often used for temporary storage during a function’s execution, such as loop counters or intermediate values. They can also be used to store information that is only needed temporarily, such as when sorting an array. The variables can be declared and initialized with any valid Ethereum data type, such as uint256, string, bool, etc.
Conclusion
In conclusion, Solidity is a programming language for writing smart contracts. This language is relatively easy to learn, but it does require some time and effort. This guide is a quick introduction to Solidity, a programming language for writing smart contracts.
This article is not meant to be an in-depth tutorial on Solidity. It is only meant to introduce the language and its functionalities.