Your fist program

int button = 0;//button is a variable which means at zero

void setup() {
  #define led 13 
  #define buttonpin 10
  pinMode(buttonpin,INPUT);
  pinMode(led,OUTPUT);
  Serial.begin(9600);
}

void loop () {
  button = digitalRead(buttonpin);
 if (button == HIGH){
 Serial.println("led on");
 digitalWrite(led,HIGH);
  delay(100);
 }else{
  Serial.println("led off") ;
  digitalWrite(led,LOW);
  delay(100);
 }
 }