Bootcamp Prep: Recursion

Recursion: Calling a function on itself

Coderbyte Challenge: First Factorial Have the function FirstFactorial(num) take the num parameter being passed and return the factorial of it (ie. if num = 4, return (4 * 3 * 2 * 1)). For the test cases, the range will be between 1 and 18.

function FirstFactorial(num) {
// Base case, when num is equal to 0, stop recursion
// if you dont have base case, then recursion will go on forever and program will crash.
  if(num === 0) {
  return 1;
  }
// this is recursive case
// it will run for all other conditions except when num is equal to 0
return num * FirstFactorial(num - 1);
}

Termination condition: base case is a form of termination condition. However what if user input is not covered by base case? Must use additional condition as back up.

function factorial(n) {
if(n < 0) {
// termination condition to prevent infinite recursion
   return;
}
if(n===0){
// base case
   return 1;
}
// recursive case
   return n * factorial(n-1);
}
factorial(-1);
factorial(5);