# C++ keyword: `for`

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### 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`

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