How do I find the index corresponding to an specific value in an array with cuda C++

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C++

indexes

CUDA

Hello every one, I am new with cuda
I have two arrays:

double* A = new double[]{1,2,3,4,5};

double* B = new double[]{2,2,2,3,3,3,4,4,4};

I want to find the index of the value of each element in A that is equal to each element in B, which in this case is:

int* index = {1,1,1,2,2,2,3,3,3};

but I get this

<pre>int* index = {0,0,0,0,0,0,0,0,0};

here is my code:

<pre>
#include "cuda_runtime.h"
#include "device_functions.h" 
#include "device_launch_parameters.h"
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <cstdlib>
#include <cuda.h>

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include "kernel.h"


using namespace std;

__global__ void add(int n, float* x, float* y)
{

	int index  = blockIdx.x * blockDim.x + threadIdx.x;
	int stride = blockDim.x * gridDim.x;
	for (int i = index; i < n; i+=stride)
	{
		y[i] = x[i] + y[i];
	}
}

__global__ void findIndex(int n, double* x, double* y, double* v)
{
	int index = threadIdx.x;

	for (int i = 0; i < n; i++)
	{
		if (y[i] = x[index])
		{
			v[index] = i;
		}
	}
}





int main() {

	double* A = new double[5]{1,2,3,4,5};
	double* B = new double[9] {2,2,2,3,3,3,4,4,4};
	double* C = new double[9];


	double* AA;
	double* BB;
	double* CC;


	cudaMallocManaged(&AA, 5 * sizeof(double));
	cudaMallocManaged(&BB, 9 * sizeof(double));
	cudaMallocManaged(&CC, 9 * sizeof(double));

	dim3 grid(9);
	findIndex << <grid, 1 >> > (9, BB,AA, CC);


	cudaDeviceSynchronize();
	for (int i = 0; i < 9; i++)
	{
		printf("{%d}", CC[i]);

	}

	int m = 0;


	return 0;


}

What I have tried:

I have tried everything but I do not get the results I want