factorial()
        
          
const factorial = (n) => {
  if (n === 0) {
    return 1;
  } else {
    return n * factorial(n - 1);
  }
};
          
        
      factorial()
        
          
public long factorial(long n) {
  if (n == 0) {
    return 1;
  } else {
    return n * factorial(n - 1);
  }
}
          
        
      factorial()
        
          
def factorial(n):
  if n == 0:
    return 1
  else:
    return n * factorial(n - 1)
          
        
      Hit any key to advance through evaluation.
factorial(4)