C++ Primer, Fifth Edition: Foundations of C++ Arithmetic Types

C++ defines a set of primitive arithmetic types that map directly to hardware storage. Imagine memory as a sequence of numbered addresses. Each byte (8 bits) is the smallest addressable unit, while a word (usually 32/64 bits) is the natural processing size.

1. Integral Types

Includes booleans (bool), characters (including Unicode char16_t, char32_t), and integers. Integers can be signed (representing negative, zero, and positive) or unsigned (values ≥ 0).

2. Memory Representation

When an int occupies one word, it spans multiple byte addresses. For instance, an object starting at address 736424 occupies 4 bytes of contiguous memory.

3. Floating-Point & Void

Floating-point types (float, double, long double) represent real numbers via machine bit patterns. The void type signifies an "empty" result; it has no values and cannot be used to declare a standard variable.

TERMINAL bash — 80x24

> Ready. Click "Run" to execute.

QUESTION 1

What is the primary difference between signed and unsigned integral types?

Signed types can represent negative values, while unsigned types are always ≥ 0.

Unsigned types use fewer bits to store numbers.

Signed types are only for floating-point numbers.

There is no difference in modern hardware.

QUESTION 2

Which of these is considered a 'Unicode character type' in C++?

short

char32_t

long long

void

QUESTION 3

What happens if you assign -1 to an unsigned 8-bit char?

The program crashes.

The value becomes 255 due to modulo arithmetic.

The value is clamped to 0.

The value remains -1.

QUESTION 4

What is the role of the 'void' type?

To store small integers.

To represent the absence of a value or a generic pointer.

To define constants that cannot change.

To handle boolean logic.

QUESTION 5

Which C++ standard guarantees apply to floating-point precision?

double must have at least as much precision as float.

float is always 32 bits and double is always 128 bits.

All floating-point types have exactly 10 significant digits.

Floating point types cannot represent zero.

Exercise 2.5: Literal Classification & Data Modeling

Applying type logic to literals and real-world scenarios.

A financial application needs to calculate mortgage payments and handle international text identifiers. You must identify the correct C++ types to maintain precision and compatibility.

1. To calculate a mortgage payment, what types would you use for the rate, principal, and payment? Why?

Solution:
You should use double or long double for all three. Mortgage calculations require high precision to minimize rounding errors over 15-30 year spans. While 'float' is smaller, 'double' typically offers 10+ significant digits, which is standard for financial math.

2. Determine the types of these literals: (a) 'a' (b) L'a' (c) 10u (d) 3.14L

Solution:
(a) char (character literal), (b) wchar_t (wide character literal), (c) unsigned int (unsigned decimal), (d) long double (extended-precision floating point).

3. Explain the difference between short, int, long, and long long.

Solution:
These are all integral types but differ in their minimum bit size. In C++: short (16 bits), int (16 bits, usually 32), long (32 bits), and long long (64 bits). This allows developers to choose a size based on memory constraints or the range of values needed.