Structures in Golang

# Introduction

Structure (`struct`) is a composite type that can be used to store different types of data. It can be used to implement more complex data structures. For instance, the items in a convenience store have attributes such as product name, category, and price. We can use a structure to represent them.

In this lab, we will learn about defining and using structures.

**Knowledge Points:**

- Definition of a structure
- Methods of a structure instance