Remove unwanted characters from char type

Question

I'm working on an ESP8266 module that needs to fetch date data from worldtimeapi, everything works fine but the problem is How do I strip of the time field off the datetime JSON response without loop.

Note: Arduino JSON library was used in deserializing the response data and it seems the library only supports char data type.

void loop ()
{
  // Initialize the request object
  HTTPClient request;
  
// Make a http request
  request.begin(dateTime);
  delay(2000);

  // Check the request status code.
int  responseCode = request.GET(); //Get the api host response code.
  Serial.print("Response code is: ");
  Serial.println(responseCode);
  if (responseCode == 200); // If the server returned OK
  {
      String responseData = request.getString();
      Serial.println("Response from the server is:");
      Serial.println(responseData);
        // Deserialize the JSON response data
       StaticJsonDocument<715> result; // Declare data storage to stack
      
      //Check for error during data deserialization
      DeserializationError error = deserializeJson(result, responseData);
      
      if (error) 
      {
        Serial.print(F("Response deserialization failed with reason: "));
        Serial.println(error.f_str());
        return;
      }

      else
      {
        char abbreviation = result["abbreviation"];  // Returns the current time zone abbreviation
        char timezone = result["timezone"]; // Returns the current time zone 
        char datetime = result["datetime"]; // "2021-03-12T17:04:0
        char date = datetime.remove(9,22); // This line throws error : request for member 'remove' in 'datetime', which is of non-class type 'char'

          
        
        Serial.print("Current time is ");
        Serial.print(datetime);
        Serial.print(" ");
        Serial.print(abbreviation);
        Serial.print(" "); 
        Serial.println(timezone);
        delay(2000);
      }
      
  }


}

Answer 1

You can use strtok to split the string on the T character:

char *datepart = strtok(datetime, "T");
char *timepart = strtok(NULL, "T");

Serial.print("The current date is: ");
Serial.println(datepart);
Serial.print("The current time is: ");
Serial.println(timepart);

An alternative is to just find the T and turn it into the NULL terminating character:

char *T = strchr(datetime, 'T');
*T = 0;

---

If you need to copy the string data into a temporary string first you can do:

char temp[strlen(datetime)+1];
strcpy(temp, datetime);

Then operate on temp instead of datetime.