# Structures

Structures are a powerful piece of Algol 68, particularly when combined with the unions described in the next chapter. In this chapter, we shall meet another mode constructor, examine complex numbers and their associated operators and learn how to construct new modes. In doing so, you will deepen your understanding of the language.

Subsections

- Structure denotations
  - Exercises
- Field selection
  - Exercises
- Mode declarations
  - Exercises
- Complex numbers
  - Exercises
- Multiples in structures
  - Exercises
- Rows of structures
  - Exercises
- Transput of structures
- Summary
  - Exercises