Key Words in C++ (C++20)

The following list displays the keywords (or reserved words), which cannot be used for any other purpose in the source code, such as variable names.

Each keyword has a specific meaning and purpose in the C++ language.

• asm – Insert assembly language code
• auto – Automatic type deduction for variables
• bool – Boolean data type (true/false)
• break – Exit from loops or switch statements
• case – Label in a switch statement
• catch – Handle exceptions in try-catch blocks
• char – Character data type
• class – Define a class
• const – Declare constants
• const_cast – Cast away constness
• continue – Skip to next iteration in a loop
• default – Default case in a switch statement
• delete – Deallocate memory allocated with new
• do – Start a do-while loop
• double – Double-precision floating point number
• dynamic_cast – Safely cast pointers or references in inheritance hierarchies
• else – Alternate branch in if-else
• enum – Declare an enumerated type
• explicit – Prevent implicit conversions for constructors
• extern – Declare variables defined elsewhere
• false – Boolean false value
• float – Floating point number
• for – Looping construct
• friend – Grant access to private/protected members of a class
• goto – Jump to a labeled statement
• if – Conditional statement
• inline – Suggest inline expansion for a function
• int – Integer data type
• long – Long integer data type
• mutable – Allow modification of member even in const object
• namespace – Define a namespace
• new – Allocate memory dynamically
• operator – Overload an operator
• private – Private access specifier
• protected – Protected access specifier
• public – Public access specifier
• register – Suggest storing variable in a CPU register
• reinterpret_cast – Low-level pointer/reference cast
• return – Return a value from a function
• short – Short integer data type
• signed – Signed integer type
• sizeof – Get size of a type or variable
• static – Static storage duration or class member
• static_cast – Compile-time cast
• struct – Define a structure
• switch – Multi-way conditional statement
• template – Define template for generic programming
• this – Pointer to current object
• throw – Throw an exception
• true – Boolean true value
• try – Define a block to catch exceptions
• typedef – Create type aliases
• typeid – Obtain type information
• typename – Specify type name in templates
• union – Define a union
• unsigned – Unsigned integer type
• using – Introduce namespace or type alias
• virtual – Declare virtual functions for polymorphism
• void – Function returns nothing
• volatile – Variable may be modified externally (e.g., hardware)
• wchar_t – Wide character type
• while – Looping construct
• alignas – Specify alignment requirement
• alignof – Get alignment of a type
• char16_t – 16-bit character type
• char32_t – 32-bit character type
• concept – Define template concept
• consteval – Evaluate at compile time
• constexpr – Constant expression
• constinit – Initialize constant at compile time
• co_await, co_return, co_yield – Coroutine keywords
• decltype – Get type of expression
• noexcept – Declare function does not throw exceptions
• nullptr – Null pointer constant
• static_assert – Compile-time assertion
• thread_local – Declare thread-local variable