From b46d61160cde02fc8f1c01ea90a7ba4c688c20a7 Mon Sep 17 00:00:00 2001
From: ToruNiina <niina.toru.68u@gmail.com>
Date: Sun, 19 Apr 2020 13:31:36 +0900
Subject: [PATCH] :pencil: add document for N-channel data

---
 README.md | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/README.md b/README.md
index bacac18..de3c2a0 100644
--- a/README.md
+++ b/README.md
@@ -184,6 +184,41 @@ int main()
 Here you can access each frame, line, and pixel intuitively by using range-based
 for loops.
 
+For the N-channel data, you need one more loop.
+
+```cpp
+#include <libasd/libasd.hpp>
+#include <fstream>
+#include <iostream>
+
+int main()
+{
+    std::ifstream ifs("example.asd");
+    const auto data = asd::read_asd<double, asd::ch<2>>(ifs);
+
+    std::cout << "x_pixel = " << data.header.x_pixel << '\n';
+    std::cout << "y_pixel = " << data.header.y_pixel << '\n';
+
+    for(auto const& frames : data.channels)
+    {
+        for(auto const& frame : frames)
+        {
+            for(auto const& line : frame)
+            {
+                for(auto const& pixel : line)
+                {
+                    std::cout << pixel << ','; // height [nm] for topography, ...
+                }
+                std::cout << '\n';
+            }
+            std::cout << "\n\n";
+        }
+    }
+    std::cout << std::flush;
+    return 0;
+}
+```
+
 You can set file version and channel as a template parameter.
 
 ```cpp