From 9f874f8aff01c27041ca03617b36e85db8cdfd63 Mon Sep 17 00:00:00 2001
From: Peter Hill <zed.three@gmail.com>
Date: Tue, 11 Jun 2019 14:28:18 +0100
Subject: [PATCH] Include example in readme

---
 README.md | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index fdb706e..9bf747d 100644
--- a/README.md
+++ b/README.md
@@ -96,4 +96,86 @@ documentation, the system will need to have doxygen and
 
 ### Examples of usage
 
-Examples codes can be found by selecting the "Examples" tab.
+Here is an example of writing a 2D array to a file, and then reading
+it back in:
+
+```cpp
+#include <iostream>
+#include <netcdf>
+
+// We are writing 2D data, a 6 x 12 grid
+constexpr int nx = 6;
+constexpr int ny = 12;
+
+// Return this in event of a problem
+constexpr int nc_err = 2;
+
+int main() {
+  // The default behavior of the C++ API is to throw an exception if
+  // an error occurs
+  try {
+    // This is the data array we will write. It will just be filled
+    // with a progression of numbers for this example.
+    int dataOut[nx][ny];
+
+    // Create some pretend data. If this wasn't an example program, we
+    // would have some real data to write, for example, model output.
+    for (int i = 0; i < nx; i++) {
+      for (int j = 0; j < ny; j++) {
+        dataOut[i][j] = i * ny + j;
+      }
+    }
+
+    // Create the file. The Replace parameter tells netCDF to overwrite
+    // this file, if it already exists.
+    netCDF::NcFile dataFile("simple_xy.nc", netCDF::NcFile::replace);
+
+    // Create netCDF dimensions
+    auto xDim = dataFile.addDim("x", nx);
+    auto yDim = dataFile.addDim("y", ny);
+
+    // Define the variable. The type of the variable in this case is
+    // ncInt (32-bit integer)
+    auto data = dataFile.addVar("data", netCDF::ncInt, {xDim, yDim});
+
+    // Write the data to the file. Although netCDF supports reading
+    // and writing subsets of data, in this case we write all the data
+    // in one operation.
+    data.putVar(dataOut);
+
+    // The file will be automatically close when the NcFile object goes
+    // out of scope. This frees up any internal netCDF resources
+    // associated with the file, and flushes any buffers.
+  } catch (netCDF::exceptions::NcException &e) {
+    std::cout << e.what() << std::endl;
+    return nc_err;
+  }
+
+  // Now read the data back in
+  try {
+    // This is the array we will read into
+    int dataIn[nx][ny];
+
+    // Open the file for read access
+    netCDF::NcFile dataFile("simple_xy.nc", netCDF::NcFile::read);
+
+    // Retrieve the variable named "data"
+    auto data = dataFile.getVar("data");
+    if (data.isNull())
+      return nc_err;
+    data.getVar(dataIn);
+
+    // Check the values.
+    for (int i = 0; i < nx; i++) {
+      for (int j = 0; j < ny; j++) {
+        if (dataIn[i][j] != i * ny + j) {
+          return nc_err;
+        }
+      }
+    }
+  } catch (netCDF::exceptions::NcException &e) {
+    std::cout << e.what() << std::endl;
+    return nc_err;
+  }
+}
+```