Mastering Blockchain Programming with Solidity

Custom data types with struct

Just like other languages such as C++, Solidity also supports defining structs. Structs are custom-defined data types that can group multiple variables in a single struct variable to form a new type.

By default, all struct values are initialized using their default values. For example, uint values will be initialized with 0; bool values will be initialized with false; and address values will be initialized with 0x0, as follows:

contract LoanStruct {    //Definition of struct    struct LoanData {        address borrower;        address lender;        uint256 loanAmount;    }}

0x0 is the short form of a specific Ethereum address, 0x0000000000000000000000000000000000000000. This address is also used for logging purposes, especially when minting ...