Smoke test for exclusive_scan

test/stdpar/tests/exclusive_scan.cpp

@@ -0,0 +1,46 @@
+#include <cstddef>
+#include <execution>
+#include <numeric>
+#include <vector>
+
+int main()
+{
+  constexpr std::size_t N = 1 << 16;
+
+  std::vector<int> in(N);
+  std::vector<int> out(N);
+
+  for (std::size_t i = 0; i < N; ++i)
+  {
+    in[i] = static_cast<int>(i + 1);
+  }
+
+  // exclusive_scan with default initial value (0)
+  std::exclusive_scan(std::execution::par, in.begin(), in.end(), out.begin(), 0);
+
+  int running_sum = 0;
+  for (std::size_t i = 0; i < N; ++i)
+  {
+    if (out[i] != running_sum)
+    {
+      return 1;
+    }
+    running_sum += in[i];
+  }
+
+  // exclusive_scan with non-zero initial value
+  const int init = 42;
+  std::exclusive_scan(std::execution::par, in.begin(), in.end(), out.begin(), init);
+
+  running_sum = init;
+  for (std::size_t i = 0; i < N; ++i)
+  {
+    if (out[i] != running_sum)
+    {
+      return 1;
+    }
+    running_sum += in[i];
+  }
+
+  return 0;
+}