function split(str) {
  if(!str.length) {
    return "";
  }
  return str[0] + split(str.slice(1));


}

//Exercise 5 - String Splitter

function split(str) {
  if(!str.length) {
    return;
  }
  return str[0] + "-" + split(str.slice(1));


}

console.log(split("hello"))

//Binary


function binary(num) {
  if (num < 2){
    return num;
  } else {
    return binary(Math.floor(num/2)).toString() + (num % 2).toString();
  }
}

binary(37);

//Factorial

var factorial = x => {
  if (x === 0) {
    return 1;
  }
  return x * factorial(x-1);
}

console.log(factorial(3))

//Fibonacci

vvar fibonacci = x => {

  if (x <= 1) {
    return 1
  }
  return fibonacci(x - 1) + fibonacci(x - 2);
}

for (i=0; i<20; i++){
console.log(fibonacci(i));
}