Println didn't print out properly

#include <ESP8266WiFi.h>

// Replace with your network credentials
const char* ssid     = "";
const char* password = "";

// Set web server port number to 80
WiFiServer server(80);

// Variable to store the HTTP request
String header;

// Auxiliar variables to store the current output state
String output1State = "empty";
String output2State = "empty";

// Assign output variables to GPIO pins
const int output1 = 1;
const int output2 = 2;

void setup() {
  Serial.begin(115200);
  // Initialize the output variables as outputs
  pinMode(output1, OUTPUT);
  pinMode(output2, OUTPUT);
  // Set outputs to LOW
  digitalWrite(output1, LOW);
  digitalWrite(output2, LOW);

  // Connect to Wi-Fi network with SSID and password
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  // Print local IP address and start web server
  Serial.println("");
  Serial.println("WiFi connected.");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  server.begin();
}

void loop(){
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
    Serial.println("New Client.");          // print a message out in the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        header += c;
        if (c == '\n') {                    // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println();
            
            // turns the GPIOs on and off
            if (header.indexOf("GET /1/empty") >= 0) {
              Serial.println("ROOM 1 empty");
              output1State = "empty";
              digitalWrite(output1, HIGH);
            } else if (header.indexOf("GET /1/occupied") >= 0) {
              Serial.println("ROOM 1 occupied");
              output1State = "occupied";
              digitalWrite(output1, LOW);
            } else if (header.indexOf("GET /2/empty") >= 0) {
              Serial.println("ROOM 2 empty");
              output2State = "empty";
              digitalWrite(output2, HIGH);
            } else if (header.indexOf("GET /2/occupied") >= 0) {
              Serial.println("ROOM 2 occupied");
              output2State = "occupied";
              digitalWrite(output2, LOW);
            }
            
            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            // CSS to style the on/off buttons 
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #195B6A; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #77878A;}</style></head>");
            
            // Web Page Heading
            client.println("<body><h1>ESP8266 WEB SERVER</h1>");
            
            // Display current state, and ON/OFF buttons for GPIO 5  
            client.println("<p>ROOM 1 - State " + output1State + "</p>");
            // If the output5State is off, it displays the ON button       
            if (output1State=="occupied") {
              client.println("<p><a href=\"/1/empty\"><button class=\"button\">EMPTY</button></a></p>");
            } else {
              client.println("<p><a href=\"/1/occupied\"><button class=\"button button2\">OCCUPIED</button></a></p>");
            } 
               
            // Display current state, and ON/OFF buttons for GPIO 4  
            client.println("<p>ROOM 2 - State " + output2State + "</p>");
            // If the output4State is off, it displays the ON button       
            if (output2State=="occupied") {
              client.println("<p><a href=\"/2/empty\"><button class=\"button\">EMPTY</button></a></p>");
            } else{
              client.println("<p><a href=\"/2/occupied\"><button class=\"button button2\">OCCUPIED</button></a></p>");
            }
            client.println("</body></html>");
            
            // The HTTP response ends with another blank line
            client.println();
            // Break out of the while loop
            break;
          } else { // if you got a newline, then clear currentLine
            currentLine = "";
          }
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}

when I upload the code, while shown in the web server state empty will show occupied , state occupied will shown empty . Anything doing wrong ?

Isn’t that exactly what your code does?

            if (output1State == "occupied") {
              client.println("<p><a href=\"/1/empty\"><button class=\"button\">EMPTY</button></a></p>");
            } else {
              client.println("<p><a href=\"/1/occupied\"><button class=\"button button2\">OCCUPIED</button></a></p>");
            }

if output1State is “occupied”, you display the EMPTY button…

blh64:
Isn’t that exactly what your code does?

            if (output1State == "occupied") {

client.println("

<a href="/1/empty"><button class=“button”>EMPTY

");
            } else {
              client.println("

<a href="/1/occupied"><button class=“button button2”>OCCUPIED

");
            }




if output1State is "occupied", you display the EMPTY button...

if output1 state, if will, showed “state empty” DISPLAY A empty Button. When I pressing the EMPTY button OUTPUT 1 state occupied. Display an occupied Button

Are you saying that on your the Serial monitor output does not match the web page?
this output

            if (header.indexOf("GET /1/empty") >= 0) {
              Serial.println("ROOM 1 empty");
              output1State = "empty";
              digitalWrite(output1, HIGH);
            } else if (header.indexOf("GET /1/occupied") >= 0) {
              Serial.println("ROOM 1 occupied");
              output1State = "occupied";
              digitalWrite(output1, LOW);
            } else if (header.indexOf("GET /2/empty") >= 0) {
              Serial.println("ROOM 2 empty");
              output2State = "empty";
              digitalWrite(output2, HIGH);
            } else if (header.indexOf("GET /2/occupied") >= 0) {
              Serial.println("ROOM 2 occupied");
              output2State = "occupied";
              digitalWrite(output2, LOW);
            }

doesn’t match this web output?

            if (output1State == "occupied") {
              client.println("<p><a href=\"/1/empty\"><button class=\"button\">EMPTY</button></a></p>");
            } else {
              client.println("<p><a href=\"/1/occupied\"><button class=\"button button2\">OCCUPIED</button></a></p>");
            }