> ## Documentation Index
> Fetch the complete documentation index at: https://base-a060aa97-eb-mini-app-ia-overhaul.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Arrays Exercise
> Exercise - Demonstrate your knowledge of arrays.
Create a contract that adheres to the following specifications.
***
## Contract
Review the contract in the starter snippet called `ArraysExercise`. It contains an array called `numbers` that is initialized with the numbers 1–10. Copy and paste this into your file.
```solidity
contract ArraysExercise {
uint[] public numbers = [1,2,3,4,5,6,7,8,9,10];
}
```
Add the following functions:
### Return a Complete Array
The compiler automatically adds a getter for individual elements in the array, but it does not automatically provide functionality to retrieve the entire array.
Write a function called `getNumbers` that returns the entire `numbers` array.
### Reset Numbers
Write a `public` function called `resetNumbers` that resets the `numbers` array to its initial value, holding the numbers from 1-10.
We'll award the pin for any solution that works, but one that **doesn't** use `.push()` is more gas-efficient!
Remember, *anyone* can call a `public` function! You'll learn how to protect functionality in another lesson.
### Append to an Existing Array
Write a function called `appendToNumbers` that takes a `uint[] calldata` array called `_toAppend`, and adds that array to the `storage` array called `numbers`, already present in the starter.
### Timestamp Saving
At the contract level, add an `address` array called `senders` and a `uint` array called `timestamps`.
Write a function called `saveTimestamp` that takes a `uint` called `_unixTimestamp` as an argument. When called, it should add the address of the caller to the end of `senders` and the `_unixTimestamp` to `timestamps`.
You'll need to research on your own to discover the correct *Special Variables and Functions* that can help you with this challenge!
### Timestamp Filtering
Write a function called `afterY2K` that takes no arguments. When called, it should return two arrays.
The first should return all timestamps that are more recent than January 1, 2000, 12:00am. To save you a click, the Unix timestamp for this date and time is `946702800`.
The second should return a list of `senders` addresses corresponding to those timestamps.
### Resets
Add `public` functions called `resetSenders` and `resetTimestamps` that reset those storage variables.
***
### Submit your Contract and Earn an NFT Badge! (BETA)
#### Hey, where'd my NFT go!?
[Testnets](/learn/deployment-to-testnet/test-networks) are not permanent! Base Goerli [will soon be sunset](https://base.mirror.xyz/kkz1-KFdUwl0n23PdyBRtnFewvO48_m-fZNzPMJehM4), in favor of Base Sepolia.
As these are separate networks with separate data, your NFTs **will not** transfer over.
**Don't worry!** We've captured the addresses of all NFT owners on Base Goerli and will include them when we release the mechanism to transfer these NFTs to mainnet later this year! You can also redeploy on Sepolia and resubmit if you'd like!
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