int led1=7;
int button=3; 
int state;

void setup() {
  // put your setup code here, to run once:
pinMode(led1,OUTPUT);
pinMode(button,INPUT);
}

void loop() {
  state=digitalRead(button);
  if(state==HIGH){
    digitalWrite(led1,LOW);
  }
  else{
    digitalWrite(led1,HIGH);
  }
}