byte led=13;   //led sto pin 13
byte button=7; //button sto pin 7

boolean btn_state=LOW; //dinw timi stin metabliti

void setup() 
{
 pinMode(led,OUTPUT);
 pinMode(button,INPUT);

}

void loop() 
{
  btn_state=digitalRead(button);
  digitalWrite(led,btn_state);
}