//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <valarray>

// template<class T> class valarray;

// indirect_array<value_type> operator[](const valarray<size_t>& vs);

#include <valarray>
#include <cassert>

int main(int, char**)
{
    {
        int a[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
                   12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
                   24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
                   36, 37, 38, 39, 40};
        const std::size_t N1 = sizeof(a)/sizeof(a[0]);
        std::size_t s[] = { 3,  4,  5,  7,  8,  9, 11, 12, 13, 15, 16, 17,
                           22, 23, 24, 26, 27, 28, 30, 31, 32, 34, 35, 36};
        const std::size_t S = sizeof(s)/sizeof(s[0]);
        std::valarray<int> v1(a, N1);
        std::valarray<std::size_t> ia(s, S);
        std::valarray<int> v(24);
        v = v1[ia];
        assert(v.size() == 24);
        assert(v[ 0] ==  3);
        assert(v[ 1] ==  4);
        assert(v[ 2] ==  5);
        assert(v[ 3] ==  7);
        assert(v[ 4] ==  8);
        assert(v[ 5] ==  9);
        assert(v[ 6] == 11);
        assert(v[ 7] == 12);
        assert(v[ 8] == 13);
        assert(v[ 9] == 15);
        assert(v[10] == 16);
        assert(v[11] == 17);
        assert(v[12] == 22);
        assert(v[13] == 23);
        assert(v[14] == 24);
        assert(v[15] == 26);
        assert(v[16] == 27);
        assert(v[17] == 28);
        assert(v[18] == 30);
        assert(v[19] == 31);
        assert(v[20] == 32);
        assert(v[21] == 34);
        assert(v[22] == 35);
        assert(v[23] == 36);
    }
    {
        int raw_data[] = {0,1,2,3,4,5,6,7,8,9};
        std::size_t idx_data[] = {0,2,4,6,8};
        std::valarray<int> data(raw_data, sizeof(raw_data)/sizeof(raw_data[0]));
        std::valarray<std::size_t> idx(idx_data, sizeof(idx_data)/sizeof(idx_data[0]));
        std::valarray<int> result = (data + 0)[idx];
        assert(result.size() == 5);
        assert(result[0] == data[idx[0]]);
        assert(result[1] == data[idx[1]]);
        assert(result[2] == data[idx[2]]);
        assert(result[3] == data[idx[3]]);
        assert(result[4] == data[idx[4]]);
    }
  return 0;
}