Labs

Resources for this lab: resources/labs

1. Write a for loop that takes the value of base, and modifies a variable (total) to base to the power of pow in the following function:

   let exponential = function(base, pow) {
     let total;
   
     /************* Your Code Here **************/
   
     /*******************************************/
   
     return total;
   
   }
   

2. The Fibonacci sequence is a series of numbers in which the first two numbers are 0 and 1. Each subsequent number is the sum of the previous two. So, the next Fibonacci number is (0+1)=1. The next is (1+1)=2. Then (1+2)=3...etc. The first two are pre-defined as 0 and 1. All subsequent numbers are calculated from there.

n	0	1	2	3	4	5	6	7	8	9	10
fib	0	1	1	2	3	5	8	13	21	34	55

Modify the following function with a while loop to print the 'nth' Fibonacci number, where the variable n is that number's position. E.g. Fibonacci number 4 is 3, fib7 is 13.

```js
let fibonacci = function(n) {
  let number;
  /************* Your Code Here **************/

  /*******************************************/
  return number;
};
```

1. Complete the following 'reduce' function such that it will return the a value equal to the all of the values of the provided array (arr) combined through some operation (op), where op is a string like +. -, *, /.

For example:

```js
reduce('+', [1,2,3]); // => 6
```

If the provided operator (op) is not one of those listed above, return the string 'invalid operator' instead.

```js
let reduce = function(op, arr) {
  let total = arr[0];
  /************ Your Code Here *************/

  /*****************************************/
  return total;
};
```

1. Complete the following isLeapYear function such that it will return true if the year provided is a leap year and false if the value is not a leap year.

Leap Years :

In the Gregorian calendar, a normal year consists of 365 days. Because the actual length of a sidereal year (the time required for the Earth to revolve once about the Sun) is actually 365.25635 days, a "leap year" of 366 days is used once every four years to eliminate the error caused by three normal (but short) years. Any year that is evenly divisible by 4 is a leap year: for example, 1988, 1992, and 1996 are leap years.

However, there is still a small error that must be accounted for. To eliminate this error, the Gregorian calendar stipulates that a year that is evenly divisible by 100 (for example, 1900) is a leap year only if it is also evenly divisible by 400.

For this reason, the following years are not leap years:

1700, 1800, 1900, 2100, 2200, 2300, 2500, 2600

This is because they are evenly divisible by 100 but not by 400.

```js
let isLeapYear = function(year) {
  let leapYear;
  /************ Your Code Here *************/

  /*****************************************/
  return leapYear;
};
```

---

Prev -- Up