Constants and literals in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a constant in C++?

A constant is a value that cannot be changed after it is set. It is declared using the const keyword.

beginner

What is a literal in C++?

A literal is a fixed value written directly in the code, like 42, 3.14, or 'a'.

beginner

How do you declare a constant integer with value 10 in C++?

You write: <code>const int number = 10;</code> This means <code>number</code> cannot be changed later.

intermediate

What is the difference between a constant and a literal?

A literal is a fixed value written in code. A constant is a named variable that holds a fixed value and cannot be changed.

intermediate

Why use constants instead of literals directly in code?

Constants make code easier to read and maintain. If the value changes, you only update it in one place.

Which keyword declares a constant in C++?

A static

B var

C let

D const

The const keyword is used to declare constants in C++.

What is the type of the literal 3.14 in C++?

A float or double

B char

C int

D bool

The literal 3.14 is a floating-point number, usually double by default.

Which of these is a valid constant declaration?

A const int x = 5;

B int const x;

C const x = 5;

D int x const = 5;

The correct syntax is const int x = 5; or int const x = 5;. Option C and D are invalid.

Can you change the value of a constant after it is set?

A No, constants cannot be changed

B Only inside functions

C Yes, anytime

D Only if declared static

Constants cannot be changed once assigned.

Which of these is a character literal in C++?

A "a"

B 'a'

C a

D char('a')

Character literals are enclosed in single quotes, like 'a'.

Explain what constants and literals are in C++ and how they differ.

Think about fixed values and named fixed values.

Describe why using constants is better than using literals directly in your code.

Imagine changing a value used many times.