diff --git a/source/libs/array/array/swap.rst b/source/libs/array/array/swap.rst
index 83ddf0d3..fb7518c8 100644
--- a/source/libs/array/array/swap.rst
+++ b/source/libs/array/array/swap.rst
@@ -30,7 +30,7 @@ Examples
   auto x = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
   auto y = array<int, 10>{{10, 9, 8, 7, 6, 5, 4, 3, 2, 1}};
   x.swap(y);
-  SPROUT_ASSERT_MSG(x[0] = 10 && y[0] == 1, "each element are swapped.");
+  SPROUT_ASSERT_MSG(x[0] == 10 && y[0] == 1, "each element are swapped.");
 
 Complexity
 ========================================