Arrays (C++/CLI and C++/CX)
The Platform::Array<T> type in C++/CX, or the array keyword in C++/CLI, declares an array of a specified type and initial value.
All Platforms
The array must be declared by using the handle-to-object (^) modifier after the closing angle bracket (>) in the declaration. The number of elements of the array is not part of the type. One array variable can refer to arrays of different sizes.
Unlike standard C++, subscripting is not a synonym for pointer arithmetic and is not commutative.
For more information about arrays, see:
Windows Runtime
Arrays are members of the Platform namespace. Arrays can be only one-dimensional.
Syntax
The first example of the syntax uses the ref new aggregate keyword to allocate an array. The second example declares a local array.
[qualifiers] [Platform::]Array<[qualifiers] array-type [,rank]>^ identifier =
ref new[Platform::]Array<initialization-type> [{initialization-list [,...]}]
[qualifiers] [Platform::]Array<[qualifiers] array-type [,rank]>^ identifier =
{initialization-list [,...]}
qualifiers
(Optional) One or more of these storage class specifiers: mutable, volatile, const, extern, static.
array-type
The type of the array variable. Valid types are Windows Runtime classes and fundamental types, ref classes and structs, value classes and structs, and native pointers (type*).
rank
(Optional) The number of dimensions of the array. Must be 1.
identifier
The name of the array variable.
initialization-type
The type of the values that initialize the array. Typically, array-type and initialization-type are the same type. However, the types can be different if there is a conversion from initialization-type to array-type—for example, if initialization-type is derived from array-type.
initialization-list
(Optional) A comma-delimited list of values in curly brackets that initialize the elements of the array. For example, if rank-size-list were (3), which declares a one-dimensional array of 3 elements, initialization list could be {1,2,3}.
Remarks
You can detect at compile time whether a type is a reference-counted array with __is_ref_array(type). For more information, see Compiler Support for Type Traits.
Requirements
Compiler option: /ZW
Examples
The following example creates a one-dimensional array that has 100 elements.
// cwr_array.cpp
// compile with: /ZW
using namespace Platform;
ref class MyClass {};
int main() {
// one-dimensional array
Array<MyClass^>^ My1DArray = ref new Array<MyClass^>(100);
My1DArray[99] = ref new MyClass();
}
Common Language Runtime
Syntax
The first example of the syntax uses the gcnew keyword to allocate an array. The second example declares a local array.
[qualifiers] [cli::]array<[qualifiers] array-type [,rank]>^ identifier =
gcnew [cli::]array<initialization-type[,rank]>(rank-size-list[,...]) [{initialization-list [,...]}]
[qualifiers] [cli::]array<[qualifiers] array-type [,rank]>^ identifier =
{initialization-list [,...]}
qualifiers
(Optional) One or more of these storage class specifiers: mutable, volatile, const, extern, static.
array-type
The type of the array variable. Valid types are Windows Runtime classes and fundamental types, ref classes and structs, value classes and structs, native pointers (type*), and native POD (plain old data) types.
rank
(Optional) The number of dimensions of the array. The default is 1; the maximum is 32. Each dimension of the array is itself an array.
identifier
The name of the array variable.
initialization-type
The type of the values that initialize the array. Typically, array-type and initialization-type are the same type. However, the types can be different if there is a conversion from initialization-type to array-type—for example, if initialization-type is derived from array-type.
rank-size-list
A comma-delimited list of the size of each dimension in the array. Alternatively, if the initialization-list parameter is specified, the compiler can deduce the size of each dimension and rank-size-list can be omitted.
initialization-list
(Optional) A comma-delimited list of values in curly brackets that initialize the elements of the array. Or a comma-delimited list of nested initialization-list items that initialize the elements in a multi-dimensional array.
For example, if rank-size-list were (3), which declares a one-dimensional array of 3 elements, initialization list could be {1,2,3}. If rank-size-list were (3,2,4), which declares a three-dimensional array of 3 elements in the first dimension, 2 elements in the second, and 4 elements in the third, initialization-list could be {{1,2,3},{0,0},{-5,10,-21,99}}.)
Remarks
array is in the Platform, default, and cli Namespaces namespace.
Like standard C++, the indices of an array are zero-based, and an array is subscripted by using square brackets ([]). Unlike standard C++, the indices of a multi-dimensional array are specified in a list of indices for each dimension instead of a set of square-bracket ([]) operators for each dimension. For example, identifier[index1, index2] instead of identifier[index1][ index2].
All managed arrays inherit from System::Array. Any method or property of System::Array can be applied directly to the array variable.
When you allocate an array whose element type is pointer-to a managed class, the elements are 0-initialized.
When you allocate an array whose element type is a value type V, the default constructor for V is applied to each array element. For more information, see .NET Framework Equivalents to C++ Native Types (C++/CLI).
At compile time, you can detect whether a type is a common language runtime (CLR) array with __is_ref_array(type). For more information, see Compiler Support for Type Traits.
Requirements
Compiler option: /clr
Examples
The following example creates a one-dimensional array that has 100 elements, and a three-dimensional array that has 3 elements in the first dimension, 5 elements in the second, and 6 elements in the third.
// clr_array.cpp
// compile with: /clr
ref class MyClass {};
int main() {
// one-dimensional array
array<MyClass ^> ^ My1DArray = gcnew array<MyClass ^>(100);
My1DArray[99] = gcnew MyClass();
// three-dimensional array
array<MyClass ^, 3> ^ My3DArray = gcnew array<MyClass ^, 3>(3, 5, 6);
My3DArray[0,0,0] = gcnew MyClass();
}