How to turn on and off relay when temp reach temp

Hi All,
i have a question, i have a nodemcu and its connected to blynk serverm i have 1 temp sensor on Virtual port and one relay port,
i do i set the relay to open and close when the temp is high and low ?

  • DS18B20 Temperature Sensor */
/#include <OneWire.h>
#include<DallasTemperature.h> 
#define ONE_WIRE_BUS 2 // DS18B20 on arduino pin2 corresponds to D4 on physical board
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature DS18B20(&oneWire);
float temp;

void setup()
{
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
  DS18B20.begin();
  timer.setInterval(1000L, getSendData);
}

void loop()
{
  timer.run(); // Initiates SimpleTimer
  Blynk.run();
}

/***************************************************
 * Send Sensor data to Blynk
 **************************************************/
void getSendData()
{
  DS18B20.requestTemperatures(); 
  temp = DS18B20.getTempCByIndex(0);
  Serial.println(temp);
  Blynk.virtualWrite(10, temp); //virtual pin V10

attached code
thanks

Please format your code correctly before support can be provided.

```cpp
CODE
```