Summary

In this lesson, you learned that:

• A structure groups values that belong together, even of different types, into one whole. Its definition lists its members and ends with };, the semicolon included.
• A variable of a structure type is created with its values in curly braces, in the order of the members: struct product bread = {"Bread", 32.5, 2};.
• You get to a member with a dot, bread.price, and use it like an ordinary variable. Text is copied into a member with strcpy, because an array can't be assigned with =.
• typedef struct { ... } Product; gives the type the name Product, so you write Product bread. This course writes structures this way.
• An array of structures, Product cart[3], holds a structure in each element: cart[i].name. Widths such as %-8s and %6.2f line up the columns of a table.
• A member can be an array or another structure, and you chain the dots and brackets: eva.birthday.year, eva.points[0].
• A structure passed to a function is copied, and so is a structure assigned with =. Changes to the copy don't change the original. Structures can't be compared with ==; compare their members.
• Through a pointer, Product *item, a function changes the original: item->count is the same as (*item).count, and you call it with &milk. const Product *item is for a function that only reads.
• A function can return a structure, and so give back several values at once.

That was the last new topic of the course. In the next lesson, the final project, you will write one bigger program step by step and use everything you have learned: variables, conditions, loops, arrays, strings, functions, pointers and structures.

But first, practice structures on a small task: a reading list.