C++ keyword: for

 

C++

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C++ language

General topics
Preprocessor Comments	Keywords Escape sequences
Flow control
Conditional execution statements
if	switch
Iteration statements (loops)
for range-for (C++11)	while do-while
Jump statements
continue - break	goto - return
Functions
Function declaration
Lambda function expression
inline specifier
Dynamic exception specifications (until C++17*)
noexcept specifier (C++11)
Exceptions
throw-expression try block	handler
Namespaces
Namespace declaration	Namespace aliases
Types
Fundamental types Enumeration types Function types	Class/struct types Union types
Specifiers
const/volatile decltype (C++11) auto (C++11)	constexpr (C++11) consteval (C++20) constinit (C++20)
Storage duration specifiers
Initialization
Default-initialization Value-initialization Zero-initialization Copy-initialization Direct-initialization	Aggregate initialization List-initialization (C++11)   Constant initialization Reference initialization

Expressions
Value categories Order of evaluation	Operators Operator precedence
Alternative representations
Literals
Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
User-defined (C++11)
Utilities
Attributes (C++11)
Types
typedef declaration
Type alias declaration (C++11)
Casts
Implicit conversions static_cast const_cast	Explicit conversions dynamic_cast reinterpret_cast
Memory allocation
new expression	delete expression
Classes
Class declaration Constructors this pointer	Access specifiers friend specifier
Class-specific function properties
Virtual function override specifier (C++11)   final specifier (C++11)	explicit (C++11) static
Special member functions
Default constructor Copy constructor Move constructor (C++11)	Copy assignment Move assignment (C++11) Destructor
Templates
Class template Function template	Template specialization Parameter packs (C++11)
Miscellaneous
Inline assembly	History of C++

 

Keywords

alignas (C++11) alignof (C++11) and and_eq asm auto (*) bitand bitor bool break case catch char char8_t (C++20) char16_t (C++11) char32_t (C++11) class compl concept (C++20) const consteval (C++20)     constexpr (C++11) constinit (C++20) const_cast continue co_await (C++20) co_return (C++20) co_yield (C++20) decltype (C++11) default delete	do double dynamic_cast else enum explicit export extern false float for friend goto if inline int long mutable namespace new noexcept (C++11)     not not_eq nullptr (C++11) operator or or_eq private protected public register	reinterpret_cast requires (C++20) return short signed sizeof (*) static static_assert (C++11) static_cast struct switch template this thread_local (C++11) throw true try typedef typeid typename union unsigned using virtual void volatile wchar_t while xor xor_eq
Identifiers with special meaning
final (C++11) import (C++20)	module (C++20) override (C++11)

 

Usage

• for loop: as the declaration of the loop

range-based for loop: as the declaration of the loop

(since C++11)

Example

Run this code

#include <iostream>
 
int main() noexcept
{
    // The following 'for' loop statement:
    // 1. (init-statement) Declares an integer named 'i' and initializes it with value '0'.
    // 2. (condition)      Checks if i is less than 3 and if not, ends the loop execution.
    // 3. (statement)      Writes out a current value of the integer 'i' to the stdout.
    // 4. (expression)     Pre-increments the integer 'i' (increases its value by 1).
    // 5.                  Returns to the point 2 (condition).
 
                                // init-statement: int i{0};
                                // condition:      i < 3
    for (int i{0}; i < 3; ++i)  // expression:     ++i
        std::cout << i;         // statement:      std::cout << i;
}

Output:

012

See also

• if statement: if, else

constexpr if statement: constexpr (constexpr if statement)	(since C++17)
consteval if statement: consteval (consteval if statement)	(since C++23)

• switch statement: switch, case
• default (as case label declaration) etc: default
• goto statement: goto
• continue statement: continue
• break statement: break
• return statement: return

co_return statement (return from a coroutine): co_return

(since C++20)

• do-while loop and while loop: do, while