for each, in

Use the for each statement to iterate through an array or collection.

All Runtimes

Syntax

for each (type identifier in expression) {
   statements
}

Parameters

• type
  The type of identifier.

• identifier
  The iteration variable that represents the collection element. When identifier is a tracking reference, you can modify the element.

• expression
  An array expression or collection. The compiler must be able to convert the collection element to the identifier type.

• statements
  One or more statements to be executed.

Remarks

The for each statement is used to iterate through a collection. It is possible to modify elements in a collection, but you cannot add or delete elements.

The statements are executed for each element in the array or collection. After the iteration has been completed for all the elements in the collection, control is transferred to the next statement following the for each block.

for each and in are context-sensitive keywords; see Context-Sensitive Keywords (C++ Component Extensions) for more information.

In the development environment, you can get F1 help on by highlighting the keyword, (for each) and pressing F1.

For more information, see,

• Iterating Over STL Collection By Using for each

• How to: Iterate Over Arrays with for each

• How to: Iterate Over a Generic Collection with for each

• How to: Iterate Over a User-Defined Collection with for each

Windows Runtime

(There are no Windows Runtime-specific remarks for this language feature.)

Requirements

Compiler option: /ZW

Examples

Example

This sample shows how to iterate through a string with for each.

// for_each_string1.cpp
// compile with: /ZW
#include <stdio.h>
using namespace Platform;

ref struct MyClass {
   property String^ MyStringProperty;
};

int main() {
   String^ MyString = ref new String("abcd");

   for each ( char c in MyString )
      wprintf("%c", c);

   wprintf("/n");

   MyClass^ x = ref new MyClass();
   x->MyStringProperty = "Testing";

   for each( char c in x->MyStringProperty )
      wprintf("%c", c);
}

Output

abcd
Testing

Common Language Runtime

The following table lists differences from the syntax shown in the All Runtimes section that are specific to C++/CLI.

Parameters

• expression
  A managed array expression or collection. The compiler must be able to convert the collection element from Object to the identifier type.

  expression evaluates to a type that implements IEnumerable, IEnumerable<T>, or a type that defines a GetEnumerator method. In the latter case, GetEnumerator should either return a type that implements IEnumerator or declares all the methods defined in IEnumerator.

Requirements

Compiler option: /clr

Examples

Example

This sample shows how to iterate through a string with for each.

// for_each_string2.cpp
// compile with: /clr
using namespace System;

ref struct MyClass {
   property String ^ MyStringProperty;
};

int main() {
   String ^ MyString = gcnew String("abcd");

   for each ( Char c in MyString )
      Console::Write(c);

   Console::WriteLine();

   MyClass ^ x = gcnew MyClass();
   x->MyStringProperty = "Testing";

   for each( Char c in x->MyStringProperty )
      Console::Write(c);
}

Output

abcd
Testing 

See Also

Concepts

Component Extensions for Runtime Platforms