#define Button 21
#define LED_1 19
#define LED_2 18
#define LED_3 17
#define LED_4 4
int t = 0;

void setup (){
 Serial.begin (9600);
 pinMode (Button, INPUT);
 pinMode (LED_1, OUTPUT);
 pinMode (LED_2, OUTPUT);
 pinMode (LED_3, OUTPUT);
 pinMode (LED_4, OUTPUT);
}

void loop (){
  re ();

  if(t == 1){
    digitalWrite (LED_1, HIGH);
    digitalWrite (LED_2, LOW);
    digitalWrite (LED_3, LOW);
    digitalWrite (LED_4, LOW);
  } 
   else if (t == 2){
    digitalWrite (LED_1, LOW);
    digitalWrite (LED_2, HIGH);
    digitalWrite (LED_3, LOW);
    digitalWrite (LED_4, LOW);
  }
   else if (t==3 ){
    digitalWrite (LED_1, LOW);
    digitalWrite (LED_2, LOW);
    digitalWrite (LED_3, HIGH);
    digitalWrite (LED_4, LOW);
  }
    else if (t==4 ){
    digitalWrite (LED_1, LOW);
    digitalWrite (LED_2, LOW);
    digitalWrite (LED_3, LOW);
    digitalWrite (LED_4, HIGH);
  }
 
}

void re (){
  int B_Read = digitalRead (Button);
  Serial.print (B_Read );
  Serial.println (t);
   
  if (B_Read == 1){
    delay (100);
    t++;
    Serial.println (t);
    if (t > 4){
      t = 1;
    }
    while(B_Read == 0){
      delay (10);
    }
   }
}

// #define DAC1 25

// int sine[360];
// int sawtooth[360];

// void setup() {
//    for (int deg = 0 ; deg < 360 ; deg++ ) {
//      //----------------------------Sine wave----------------
//      sine[deg] = int(128 + 127  * sin(deg * PI / 180));
//      //------------------Sawtooth---------------------------
//      sawtooth[deg] = map(deg, 0, 360, 0, 255);
//    }
// }

// void sine_wave() {
//    for (int deg = 0 ; deg < 360 ; deg ++ ) {
//      dacWrite(DAC1, sine[deg]); 
//      delay (3);   
//    }
// }

// void sawtooth_wave() {
//    for (int deg = 0 ; deg < 360 ; deg ++ ) {
//      dacWrite(DAC1, sawtooth[deg]); 
//      delay (3);   
//    }
// }

// void square_wave() {
//   dacWrite(DAC1, 0);
//   delay (500);
//   dacWrite(DAC1, 255);
//   delay (500);
// }

// void loop() {
//   //sawtooth_wave()
//   //sine_wave();
//   square_wave();
// }