Not declared in this scope problem

Hi, I'm trying to use 4 Arduino RFID scanners to signal a piezo when all 4 RFID scanners have a card on top. I'm quite new to coding so I might have some obvious mistakes.
This here is my code:

#include <SPI.h>
#include <MFRC522.h>

// PIN Numbers : RESET + SDAs
#define RST_PIN         9
#define SS_1_PIN        10
#define SS_2_PIN        8
#define SS_3_PIN        7
#define SS_4_PIN        6
int piezoPin = 8;

// List of Tags UIDs that are allowed to open the puzzle
byte tagarray[][4] = {
  {0x4B, 0x17, 0xBC, 0x79},
  {0x8A, 0x2B, 0xBC, 0x79}, 
  {0x81, 0x29, 0xBC, 0x79},
  {0xE6, 0xDF, 0xBB, 0x79},
};

// Inlocking status :
int tagcount = 0;
bool access = false;

#define NR_OF_READERS   4

byte ssPins[] = {SS_1_PIN, SS_2_PIN, SS_3_PIN, SS_4_PIN};

// Create an MFRC522 instance :
MFRC522 mfrc522[NR_OF_READERS];

/**
   Initialize.
*/
void setup() {

  Serial.begin(9600);           // Initialize serial communications with the PC
  while (!Serial);              // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)

  SPI.begin();                  // Init SPI bus


  /* looking for MFRC522 readers */
  for (uint8_t reader = 0; reader < NR_OF_READERS; reader++) {
    mfrc522[reader].PCD_Init(ssPins[reader], RST_PIN);
    Serial.print(F("Reader "));
    Serial.print(reader);
    Serial.print(F(": "));
    mfrc522[reader].PCD_DumpVersionToSerial();
    //mfrc522[reader].PCD_SetAntennaGain(mfrc522[reader].RxGain_max);
  }
}

/*
   Main loop.
*/

void loop() {

  for (uint8_t reader = 0; reader < NR_OF_READERS; reader++) {

    // Looking for new cards
    if (mfrc522[reader].PICC_IsNewCardPresent() && mfrc522[reader].PICC_ReadCardSerial()) {
      Serial.print(F("Reader "));
      Serial.print(reader);

      // Show some details of the PICC (that is: the tag/card)
      Serial.print(F(": Card UID:"));
      dump_byte_array(mfrc522[reader].uid.uidByte, mfrc522[reader].uid.size);
      Serial.println();

      for (int x = 0; x < sizeof(tagarray); x++)                  // tagarray's row
      {
        for (int i = 0; i < mfrc522[reader].uid.size; i++)        //tagarray's columns
        {
          if ( mfrc522[reader].uid.uidByte[i] != tagarray[x][i])  //Comparing the UID in the buffer to the UID in the tag array.
          {
            DenyingTag();
            break;
          }
          else
          {
            if (i == mfrc522[reader].uid.size - 1)                // Test if we browesed the whole UID.
            {
              AllowTag();
            }
            else
            {
              continue;                                           // We still didn't reach the last cell/column : continue testing!
            }
          }
        }
        if (access) break;                                        // If the Tag is allowed, quit the test.
      }


      if (access)
      {
if (tagcount == NR_OF_READERS)
        {
              Piezo();
        }
        else
        {
          MoreTagsNeeded();
        }
      }
      else
      {
        UnknownTag();
      }
      /*Serial.print(F("PICC type: "));
        MFRC522::PICC_Type piccType = mfrc522[reader].PICC_GetType(mfrc522[reader].uid.sak);
        Serial.println(mfrc522[reader].PICC_GetTypeName(piccType));*/
      // Halt PICC
      mfrc522[reader].PICC_HaltA();
      // Stop encryption on PCD
      mfrc522[reader].PCD_StopCrypto1();
    } //if (mfrc522[reader].PICC_IsNewC..
  } //for(uint8_t reader..
}

/**
   Helper routine to dump a byte array as hex values to Serial.
*/
void dump_byte_array(byte * buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }
}

void printTagcount() {
  Serial.print("Tag n°");
  Serial.println(tagcount);
}

void DenyingTag()
{
  tagcount = tagcount;
  access = false;
}

void AllowTag()
{
  tagcount = tagcount + 1;
  access = true;
}

void Initialize()
{
  tagcount = 0;
  access = false;
}

void Piezo()
  Serial.println("Congratulations!");
  tone(piezoPin, 1000, 500);

  //tone(piezoPin, 1000, 500);
  //delay(1000);

}
void MoreTagsNeeded()
{
  printTagcount();
  Serial.println("System needs more cards");
 tone(piezoPin, 1000, 500);
  access = false;
}

void UnknownTag()
{
  Serial.println("This Tag isn't allowed!");
  printTagcount();
 tone(piezoPin, 1000, 500);
}
}

This is the error message I get:

Arduino: 1.8.13 (Windows 10), Board: "Arduino Uno"





















C:\Users\190240\Desktop\4_RFID_Readers\4_RFID_Readers.ino: In function 'void loop()':

4_RFID_Readers:100:15: error: 'Piezo' was not declared in this scope

               Piezo();

               ^~~~~

C:\Users\190240\Desktop\4_RFID_Readers\4_RFID_Readers.ino:100:15: note: suggested alternative: 'fileno'

               Piezo();

               ^~~~~

               fileno

4_RFID_Readers:104:11: error: 'MoreTagsNeeded' was not declared in this scope

           MoreTagsNeeded();

           ^~~~~~~~~~~~~~

4_RFID_Readers:109:9: error: 'UnknownTag' was not declared in this scope

         UnknownTag();

         ^~~~~~~~~~

C:\Users\190240\Desktop\4_RFID_Readers\4_RFID_Readers.ino:109:9: note: suggested alternative: 'AllowTag'

         UnknownTag();

         ^~~~~~~~~~

         AllowTag

C:\Users\190240\Desktop\4_RFID_Readers\4_RFID_Readers.ino: At global scope:

4_RFID_Readers:156:3: error: expected initializer before 'Serial'

   Serial.println("Congratulations!");

   ^~~~~~

4_RFID_Readers:157:7: error: expected constructor, destructor, or type conversion before '(' token

   tone(piezoPin, 1000, 500);

       ^

4_RFID_Readers:162:1: error: expected declaration before '}' token

 }

 ^

exit status 1

'Piezo' was not declared in this scope



This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

It comes up with Piezo not being declared and I don't know why. Any help would be appreciated!
Cheers!

void Piezo()
Serial.println("Congratulations!");
tone(piezoPin, 1000, 500);

//tone(piezoPin, 1000, 500);
//delay(1000);
}

No opening { in the function definition

Thanks a lot for the help, it worked after that.

First thing I noticed…

Second thing…

there may be more.

OK thanks for the help

to find the place where in your code the error CAUSES the error

click the "copy error messages" button.
Paste the clipboad-content into a texteditor by pressing Ctrl-V and search for

: error:

pay attention to the SPACE between the first double-point and the "e"

doublepoint-SPACE-error-doublepoint ": error:

This lead you to that part of the error-messages that tells you the line and the columm
where the error OCCURS.
OCCURING is NOT always the same place as where the error starts
best regards Stefan

What’s a ‘double point’ ?
A colon ?

Yes a colon. Thanks for asking. German is my native language. And the character ":" in german is called "Doppelpunkt" as a word by word translation double-point.
So learned something new I must have missed learning very early when I was learning english.

Opposite "weird" thing with the letter "W" in english "double-U"

best regards Stefan