Fix swap chain chapter not describing required include

Overv · Overv · commit e3036d67e01b · 2017-01-13T23:25:33.000+01:00
diff --git a/03_Drawing_a_triangle/01_Presentation/01_Swap_chain.md b/03_Drawing_a_triangle/01_Presentation/01_Swap_chain.md
@@ -344,15 +344,15 @@ VkExtent2D chooseSwapExtent(const VkSurfaceCapabilitiesKHR& capabilities) {
 
         actualExtent.width = std::max(capabilities.minImageExtent.width, std::min(capabilities.maxImageExtent.width, actualExtent.width));
         actualExtent.height = std::max(capabilities.minImageExtent.height, std::min(capabilities.maxImageExtent.height, actualExtent.height));
-        
+
         return actualExtent;
     }
 }
 ```
 
 The `max` and `min` functions are used here to clamp the value of `WIDTH` and
 `HEIGHT` between the allowed minimum and maximum extents that are supported by
-the implementation.
+the implementation. Make sure to include the `<algorithm>` header to use them.
 
 ## Creating the swap chain
 
@@ -585,4 +585,4 @@ We now have a set of images that can be drawn onto and can be presented to the
 window. The next two chapters will cover how we can set up the images as render
 targets and then we start looking into the actual drawing commands!
 
-[Full code listing](/code/swap_chain_creation.cpp)
+[Full code listing](/code/swap_chain_creation.cpp)
