--- layout: stdlib-reference --- # interface IRWArray\ *Inherits from:* [IArray](../iarray-01/index.html)\<[T](../iarray-01/index.html#typeparam-T)\> ## Description Represents types that provide a subscript operator so that they can be used like a mutable array. ## Generic Parameters #### T The element type returned by the subscript operator. ## Methods * [subscript](subscript) ## Remarks This interface is implemented by Array, vector, matrix, StructuredBuffer and RWStructuredBuffer types. ## Example The follow example shows how to define a generic function uses the IRWArray interface to mutate an array-like value. ```csharp void writeToArray>(inout T array, int index, U value) { array[index] = value; } void writeToBuffer>(T array, int index, U value) { array[index] = value; } U readFromArray>(T array, int index) { return array[index]; } //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer RWStructuredBuffer outputBuffer; [numthreads(1, 1, 1)] void computeMain(int3 dispatchThreadID: SV_DispatchThreadID) { float arr[3] = { 1.0, 2.0, 3.0 }; float4 v = float4(1.0, 2.0, 3.0, 4.0); float2x2 m = float2x2(1.0, 2.0, 3.0, 4.0); // treat `outputBuffer` as a mutable array of `float`. writeToBuffer(outputBuffer, 0, 1.0f); // treat `arr` as a mutable array of `float`. writeToArray(arr, 0, 4.0f); outputBuffer[1] = readFromArray(arr, 0); // 4.0 // treat `v` as a mutable array of `float`. writeToArray(v, 3, 3.0f); outputBuffer[2] = readFromArray(v, 3); // 3.0 // treat `m` as a mutable array of `float2`. writeToArray(m, 1, float2(10.0f, 20.0f)); outputBuffer[3] = readFromArray(m, 1).x + readFromArray(m, 1).y; // 30.0 writeToBuffer(outputBuffer, 0, readFromArray(outputBuffer, 0)); } ```