More C++: Datatypes. (Qualifiers, Bit Fields, ...)

Note: Much of my programming has been done in JS, so you could say I think in JavaScript. So, from that perspective...

Based on Module 3: Datatypes of Bill Weinman's LinkedIn course.

Covered in this chapter: 

Overview of data types

Integer Types

Integer Sizes

Fixed-Size Integers

Floating-point types

Characters and strings

Character escape sequences

Qualifiers

References

Structured data

Bit fields

Enumerations

Unions

Defining types with typedef

The 'void' type

The 'auto' type

Unambiguous null pointer constant

Challenge: A library card data structure

Solution to challenge

Qualifiers

CV Qualifiers

const -- makes program throw an error if reassignment is attempted

mutable

volatile

Storage Duration Qualifiers

static -- lets a variable persist outside of the block in which it was defined

register

extern

Bit Fields

Allow you to pack multiple values into less space

Avoid in threaded programming

Use when storage space comes at a premium

Can behave differently on different OSs

Enumerations

Type safe "alternative" to preprocessor macros

Behave kind of like constants 

Use mostly for grouping scalar constants together when they have a common usage

Enumerated types have integer values

Unions

Data structure that allows you to use the same memory space for different types

Sometimes used for crude polymorphism (multiple representations of same data)

Defining Types: TypeDef

A typedef can be used as an alias for a type

Quiz

Any valid type may be a member of a struct

The 'cstdint' header allows you to specify size of integers, both signed and unsigned

You would use the 'int32_t' type when you need a signed int with a fixed size of 32 bits (other options are 8, 16, 64)

The primitive integer types are not guaranteed to be specific sizes

correct format to concatenate two primitive strings in C++: const char * cstring = "String" " and another string";

Once defined, a reference can never be re-assigned.

The types defined in the 'cstdint' header are guaranteed to be consistent sizes.

Floating point types sacrifice precision for scale.

The special nullptr value is used to provide an unambiguous null value for pointers.