BTC ticker Wemos mini with oled shield

BTC_ticker.ino

#include <ESP8266WiFi.h>
#include <ArduinoJson.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// SCL GPIO5
// SDA GPIO4
#define OLED_RESET 0  // GPIO0
Adafruit_SSD1306 display(OLED_RESET);

#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2


#if (SSD1306_LCDHEIGHT != 48)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif

const char* ssid     = "ssid";          
const char* password = "password"; 

const char* host = "api.coindesk.com";

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.print("connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  // initialize with the I2C addr 0x3C (for the 64x48)
   // Clear the buffer.
  display.clearDisplay();
  display.display();
}

void loop() { 
 
  WiFiClient client;
  const int httpPort = 80;
  if (!client.connect(host, httpPort)) {
    return;
  }
  
  String url = "/v1/bpi/currentprice.json";
  
  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + host + "\r\n" + 
               "Connection: close\r\n\r\n");
  delay(100);
  

  String answer;
  while(client.available()){
    String line = client.readStringUntil('\r');
    answer += line;
  }

  client.stop();
  
  String jsonAnswer;
  int jsonIndex;

  for (int i = 0; i < answer.length(); i++) {
    if (answer[i] == '{') {
      jsonIndex = i;
      break;
    }
  }

  // Lettura dei dati JSON
  jsonAnswer = answer.substring(jsonIndex);
  jsonAnswer.trim();

  // Ottenimento del prezzo come valore float
  int rateIndex = jsonAnswer.indexOf("rate_float");
  String priceString = jsonAnswer.substring(rateIndex + 12, rateIndex + 18);
  priceString.trim();
  float price = priceString.toFloat();
  Serial.println(price);
  
if(price > 0){
   display.clearDisplay();
   display.setTextSize(2);
   display.setTextColor(WHITE);
   display.setCursor(0,0);
   display.println(price);  
   display.display();
}

  delay(10000);
}