Blink 2

const int LED = 13; // port of LED
const int Button = 7; // port of button

int val = 0; // state of the button
int state = 0; //0=LED off // 1 =LED on

void setup() {
  pinMode(LED, OUTPUT); //LED(port 13) is output
  pinMode(Button, INPUT); //Button(port 7) is input
}

void loop() {
  val = digitalRead(Button); //val reads and stores the
                             //state of button

  // check whether button has been pressed on
  if (val ==HIGH){
    state = 1 - state;
  }
  if (state == 1) {
    digitalWrite(LED, HIGH); //turns LED(port 13) on
  } else {
    digitalWrite(LED, LOW); //if val evals not HIGH,
                            //turn off port 13
  }
}