int Led_State = 0;
byte LED_Pin = 7;
byte Button_Pin = 12;
int Button_Old = 1;
int Button_Now = 1;
bool off = 1;
bool on = 0;
void setup (){
pinMode (LED_Pin,OUTPUT);
pinMode (Button_Pin,INPUT);
digitalWrite(LED_Pin,off);
}
void loop (){
Button_Now = digitalRead(Button_Pin);
if(Button_Old==1 && Button_Now ==0){
if(Led_State==0){
digitalWrite(LED_Pin,on);
Led_State=1;
}else{
  digitalWrite(LED_Pin,off);
  Led_State = 0;
}
}
Button_Old=Button_Now;
delay(100);
}