int btn_pin_no=5;
bool btn_state= false;
int led_blue =7;
int led_purple =6;
int led_yellow = 3;

void setup() {
  pinMode(7, OUTPUT);//led_blue
  pinMode(6, OUTPUT);//led_purple
  pinMode(3, OUTPUT);//led_yellow
  pinMode(5, INPUT_PULLUP);//push_button
}

void loop() {
  btn_state=digitalRead(btn_pin_no);
  if (btn_state == true){
      digitalWrite(6,HIGH);
      delay(1000);
      digitalWrite(6, LOW);
      delay(1000);
  }
  else{
    digitalWrite(7, HIGH);
    digitalWrite(3, HIGH);
    delay(1000);
    digitalWrite(7, LOW);
    digitalWrite(3, LOW);
    delay(1000);
  }
}