added demo function to example/main.go for GenerateCodeCustom (#53)

example/main.go

@@ -6,10 +6,12 @@ import (
 
 	"bufio"
 	"bytes"
+	"encoding/base32"
 	"fmt"
 	"image/png"
 	"io/ioutil"
 	"os"
+	"time"
 )
 
 func display(key *otp.Key, data []byte) {
@@ -30,6 +32,22 @@ func promptForPasscode() string {
 	return text
 }
 
+// Demo function, not used in main
+// Generates Passcode using a UTF-8 (not base32) secret and custom paramters
+func GeneratePassCode(utf8string string) string{
+        secret := base32.StdEncoding.EncodeToString([]byte(utf8string))
+        passcode, err := totp.GenerateCodeCustom(secret, time.Now(), totp.ValidateOpts{
+                Period:    30,
+                Skew:      1,
+                Digits:    otp.DigitsSix,
+                Algorithm: otp.AlgorithmSHA512,
+        })
+        if err != nil {
+                panic(err)
+        }
+        return passcode
+}
+
 func main() {
 	key, err := totp.Generate(totp.GenerateOpts{
 		Issuer:      "Example.com",