Ethereum: How datatypes work in solidity?

How ​​Solid State Data Types Work: A Guide

When diving into the world of smart contracts on the Ethereum blockchain, one of the most fundamental concepts to understand is the data types used in the Solidity programming language. In this article, we will explore how data types work in Solidity and provide a detailed explanation of their use.

EVM Data Types

The EVM (Ethereum Virtual Machine) uses a 32-byte key-value store to store data. Contracts access this store using the “contract address” syntax. However, this store is not directly accessible outside of the contract. To interact with external data, Solidity uses its own data types.

Integers (Uint)

Integers in Solidity are stored as 32-bit unsigned integers (uint). These integers can contain values ​​ranging from 0 to 2^32 – 1. For example:

pragma solidity ^ 0,8,0;
contract SimpleStorage {
uint public counter;
function increment() public {
counter++;
}
}

When we call the increment function, the contract increments a local variable and updates its value in storage.

Strings (String)

The Solidity string data type is used to store strings of characters. Strings are defined using the `string'' keyword:

pragma solidity ^ 0,8,0;
contract MyContract {
public string message;
function setMessage(string memory _message) public {
message = _message;
}
}

When we call the setMessagefunction, it updates a local variable and stores the input string in storage.

pragma strength ^ 0,8,0;
contract MyContract {
bytes public image;
function setImage(bytes memory _image) public {
image = _image;
}
}

When we call the setImage` function, it updates a local variable and stores the input byte array in storage.

Address (address)

In Solidity, addresses are used to represent the contract’s own address. Addresses are represented as 40-byte hexadecimal strings:

pragma solidity ^ 0,8,0;
contract MyContract {
address public owner;
}

The owner variable is initialized with a random address.

Data Type Comparison

| Data Type | Usage |

| — | — |

| uint | Integer (32-bit) |

| string | String |

| bytes | Binary data (4-element array) |

| address | Custom contract address |

Conclusion

In conclusion, Solidity provides several built-in data types that allow developers to store and manipulate various types of data within their contracts. Understanding the use of these data types is essential to creating efficient and scalable smart contracts.

By learning how to use data types in Solidity, you can write more efficient and robust smart contracts that interact with external data in a secure and controlled way.