#include <LiquidCrystal.h>

LiquidCrystal lcd(18, 5, 17, 16, 4, 0);
byte ledpin=27;
byte buzzer=26;
byte ledstate=false;
byte buzzerstate=false;
int ch=0;


void setup() {
Serial.begin(115200);
pinMode(ledpin, OUTPUT);
pinMode(buzzer,OUTPUT);
lcd.begin(16, 2);
}

void a(){
  if (ledstate=!ledstate){
    digitalWrite(ledpin, HIGH);
  }
    else{
      digitalWrite(ledpin, LOW);
    }
  }
  

void b(){
  if(buzzerstate=!buzzerstate){
    digitalWrite(buzzer, HIGH);}
    else{
      digitalWrite(buzzer, LOW);
      
    
  }
}
void c(){
  if (buzzerstate){
    lcd.setCursor(3,0);
    lcd.print("buzzer on");
    }
    else{
      lcd.setCursor(3,0);
    lcd.print("buzzer off");
    }
  if(ledstate){
    lcd.setCursor(3,1);
    lcd.print("led on");
  }
  else{
    lcd.setCursor(3,1);
    lcd.print("led off");
  }
}
void d(){
  lcd.clear();
}
void loop() {}
void serialEvent() {
while (Serial.available()) {
char ch = Serial.read();
Serial.print(ch);
switch (ch){
case '0':
 a(); 

break;
case '1':
b();
break;
case '2':
c();
break;
case '3':
d();
break;
}
}
}