firebase arduino error

i got error below how to fix it ~~~/Users/huifengchen/Documents/Arduino/libraries/firebase-arduino-master/src/FirebaseHttpClient_Esp8266.cpp: In member function 'virtual std::string FirebaseHttpClientEsp8266::errorToString(int)': /Users/huifengchen/Documents/Arduino/libraries/firebase-arduino-master/src/FirebaseHttpClient_Esp8266.cpp:83:11: error: 'errorToString' is not a member of 'HTTPClient' return HTTPClient::errorToString(error_code).c_str();

Did you miss the part about posting your code when you read the “how to use this forum-please read” stickies?

https://github.com/firebase/firebase-arduino

"The Arduino library is under heavy development, experimental, unversioned and its API is not stable."

Can you build any of the included examples?

I had the same error and this the code

//
// Copyright 2015 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the “License”);
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an “AS IS” BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

// FirebaseDemo_ESP8266 is a sample that demo the different functions
// of the FirebaseArduino API.

#include <ESP8266WiFi.h>
#include <FirebaseArduino.h>

// Set these to run example.
#define FIREBASE_HOST “example.firebaseio.com
#define FIREBASE_AUTH “token_or_secret”
#define WIFI_SSID “SSID”
#define WIFI_PASSWORD “PASSWORD”

void setup() {
Serial.begin(9600);

// connect to wifi.
WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
Serial.print(“connecting”);
while (WiFi.status() != WL_CONNECTED) {
Serial.print(".");
delay(500);
}
Serial.println();
Serial.print("connected: ");
Serial.println(WiFi.localIP());

Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH);
}

int n = 0;

void loop() {
// set value
Firebase.setFloat(“number”, 42.0);
// handle error
if (Firebase.failed()) {
Serial.print(“setting /number failed:”);
Serial.println(Firebase.error());
return;
}
delay(1000);

// update value
Firebase.setFloat(“number”, 43.0);
// handle error
if (Firebase.failed()) {
Serial.print(“setting /number failed:”);
Serial.println(Firebase.error());
return;
}
delay(1000);

// get value
Serial.print("number: ");
Serial.println(Firebase.getFloat(“number”));
delay(1000);

// remove value
Firebase.remove(“number”);
delay(1000);

// set string value
Firebase.setString(“message”, “hello world”);
// handle error
if (Firebase.failed()) {
Serial.print(“setting /message failed:”);
Serial.println(Firebase.error());
return;
}
delay(1000);

// set bool value
Firebase.setBool(“truth”, false);
// handle error
if (Firebase.failed()) {
Serial.print(“setting /truth failed:”);
Serial.println(Firebase.error());
return;
}
delay(1000);

// append a new value to /logs
String name = Firebase.pushInt(“logs”, n++);
// handle error
if (Firebase.failed()) {
Serial.print(“pushing /logs failed:”);
Serial.println(Firebase.error());
return;
}
Serial.print(“pushed: /logs/”);
Serial.println(name);
delay(1000);
}

in some website, they recommended adding this code “open FirebaseHttpClient.h file, and paste following fingerprint =>
6F D0 9A 52 C0 E9 E4 CD A0 D3 02 A4 B7 A1 92 38 2D CA 2F 26”

so I modify the FirebaseHttpClient.h by :

#ifndef FIREBASE_HTTP_CLIENT_H
#define FIREBASE_HTTP_CLIENT_H

#include

#include “Arduino.h”
#include “Stream.h”

struct HttpStatus {
static const int TEMPORARY_REDIRECT = 307;
};

class FirebaseHttpClient {
public:
static FirebaseHttpClient* create();

virtual void setReuseConnection(bool reuse) = 0;
virtual void begin(const std::string& url) = 0;
virtual void begin(const std::string& host, const std::string& path) = 0;

virtual void end() = 0;

virtual void addHeader(const std::string& name, const std::string& value) = 0;
virtual void collectHeaders(const char* header_keys,
const int header_key_count) = 0;
virtual std::string header(const std::string& name) = 0;

virtual int sendRequest(const std::string& method, const std::string& data) = 0;

virtual std::string getString() = 0;

virtual Stream* getStreamPtr() = 0;

virtual std::string errorToString(int error_code) = 0;

virtual bool connected() = 0;

protected:
static const uint16_t kFirebasePort = 443;
};

static const char kFirebaseFingerprint =
“6F D0 9A 52 C0 E9 E4 CD A0 D3 02 A4 B7 A1 92 38 2D CA 2F 26”; // 2019-04

#endif // FIREBASE_HTTP_CLIENT_H

and the error changed to :

C:\Users\khade\Documents\Arduino\libraries\firebase-arduino-master\src\FirebaseHttpClient_Esp8266.cpp: In member function ‘virtual std::string FirebaseHttpClientEsp8266::errorToString(int)’:

C:\Users\khade\Documents\Arduino\libraries\firebase-arduino-master\src\FirebaseHttpClient_Esp8266.cpp:83:11: error: ‘errorToString’ is not a member of ‘HTTPClient’

return HTTPClient::errorToString(error_code).c_str();

any help ???