Added usage at code part

README.md

@@ -133,6 +133,106 @@ Note: `slash` style similar to `jsonpointer` style, but `slash` style doesn't st
 
 Note: `dot-bracket` style similar to `dot` style, but `dot-bracket` style uses square brackets for array indexes.
 
+### Usage on code
+
+    package main
+
+    import (
+    	"bytes"
+    	"encoding/json"
+    	"github.com/yukithm/json2csv"
+    	"log"
+    	"os"
+    )
+
+    func main() {
+    	b := &bytes.Buffer{}
+    	wr := json2csv.NewCSVWriter(b)
+    	j, _ := os.ReadFile("your-input-path\\input.json")
+    	var x []map[string]interface{}
+
+    	// unMarshall json
+    	err := json.Unmarshal(j, &x)
+    	if err != nil {
+    		log.Fatal(err)
+    	}
+
+    	// convert json to CSV
+    	csv, err := json2csv.JSON2CSV(x)
+    	if err != nil {
+    		log.Fatal(err)
+    	}
+
+    	// CSV bytes convert & writing...
+    	err = wr.WriteCSV(csv)
+    	if err != nil {
+    		log.Fatal(err)
+    	}
+    	wr.Flush()
+    	got := b.String()
+
+    	//Following line prints CSV
+    	println(got)
+
+    	// create file and append if you want
+    	createFileAppendText("output.csv", got)
+    }
+
+    //
+    func createFileAppendText(filename string, text string) {
+    	f, err := os.OpenFile(filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
+    	if err != nil {
+    		panic(err)
+    	}
+
+    	defer f.Close()
+
+    	if _, err = f.WriteString(text); err != nil {
+    		panic(err)
+    	}
+    }
+
+
+***input.json;***
+
+    [
+      {
+        "Name": "Japan",
+        "Capital": "Tokyo",
+        "Continent": "Asia"
+      },
+      {
+        "Name": "Germany",
+        "Capital": "Berlin",
+        "Continent": "Europe"
+      },
+      {
+        "Name": "Turkey",
+        "Capital": "Ankara",
+        "Continent": "Europe"
+      },
+      {
+        "Name": "Greece",
+        "Capital": "Athens",
+        "Continent": "Europe"
+      },
+      {
+        "Name": "Israel",
+        "Capital": "Jerusalem",
+        "Continent": "Asia"
+      }
+    ]
+
+***output.csv***
+
+    /Capital,/Continent,/Name
+    Tokyo,Asia,Japan
+    Berlin,Europe,Germany
+    Ankara,Europe,Turkey
+    Athens,Europe,Greece
+    Jerusalem,Asia,Israel
+
+
 
 License
 -------