Blockchain By Example

Variable state types

In our code, we used only two basic variable types:

• uint256
• address

The first represents an unsigned integer of 256 bits. Solidity deals with signed and unsigned integers of various sizes, and to declare an integer, we use one of the keywords, int or uint, for signed and unsigned integers of 8 to 256 bits (uint8 to uint256, in steps of 8). The type address is a dedicated type that holds a 20-byte value (the size of an address), to represent an Ethereum account's address.