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What are the differences between struct and class in C++

In C++ is there any reason to use a Struct inside of a Class outside of making your own linked list or b-tree?

I’ve taken a few programming courses in college, but haven’t really thought about this until now. It seems like there wouldn’t be any benefit from using a struct inside of a class, but I don’t have enough experience to know what situations really require certain things. I’m hoping that you experienced programmers can shed some light on this for me.

Answer 1

Here is a complex scenario: records of sub-records.

struct Title_Record
{
    unsigned int id_title;
    std::string  title_text;  // std::string is actually a struct / class.
};

struct Category_Record
{
    unsigned int id_category;
    std::string  category_text;
};

// A record of [id_ingredient, id_title, id_category],
class Ingredient_Entry
{
    unsigned int id_ingredient;
    Title_Record  title;        // Use ID field only for storing in database (foreign key).
                                // But also contain the record for local access.
    Category_Record  category;  // Use ID field only for storing in database (foreign key).

.
};

Every ingredient entry has a title and a category. The title and categories are separate records so that ingredients can share common titles and categories.

Usage:
Title_Record title_table[30]; // Database table of 30 titles.
Category_Record category_table[30]; // Database table of 30 categories.

Remember that the keywords struct and class only differ in their default accessibility.