Problem from real time clock value convert to varaible

Projects Programming
1 
#include <WiFi.h>
#include "time.h"

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

const char* ntpServer = "asia.pool.ntp.org";
const long  gmtOffset_sec = 28800;
const int   daylightOffset_sec = 28800;

void printLocalTime()
{
  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) {
    Serial.println("Failed to obtain time");
    return;
  }
  Serial.println(&timeinfo, "%B %d %Y %H:%M:%S");
}

void setup()
{
  Serial.begin(115200);
  //connect to WiFi
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" CONNECTED");

  //init and get the time
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
  printLocalTime();

  //disconnect WiFi as it's no longer needed
  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF);
}

void loop()
{
  delay(1000);
  printLocalTime();
}

if wan use the %d %Y %H:%M:%S the get the variable like
hr = %H;
A = hr + 3 + 5
to get the answer A

2 
  Serial.println(&timeinfo, "%B %d %Y %H:%M:%S");

The .println() function doesn't have the feature you are trying to use.

When the documentation says "format", it does not mean like the C library 'printf' function.

If you want values from the 'struct tm' you can look at the definition of 'struct tm' in the library you are using.