i'm struggling with the same. as of now i could only make tx version=0 deployments work. this is, `nile deploy` without going through an account

_This answer was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Newton

anybody manged to declare contracts with the new nile?

```
Error: AssertionError: Sender must be passed explicitly when making a direct declaration using --no_wallet.
```

I saw a hardhat issue aswel

must be an upstream thing

https://docs.starknet.io/docs/Blocks/transactions/#calculating-the-hash-of-a-v1-declare-transaction

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

An error “AssertionError: Sender must be passed explicitly when making a direct declaration using —no_wallet.” using the new nile?

Hello! This is day 6 of the 17 days of the Cairo Challenge. And I have no idea how to solve the [playground](https://www.cairo-lang.org/playground/) exercise “Dynamic allocation”.  Perhaps you can help me?

```
// Dynamic allocation in Cairo is done using the `alloc` function,
// which itself is implemented in Cairo using the
// [segments](https://www.cairo-lang.org/docs/how_cairo_works/segments.html) mechanism.
// Thanks to this mechanism, `alloc` allocates an array of an arbitrary size,
// which does not need to be specified in the call.
//
// The function `sqr_array` should compute and return an array
// of the square values of a given array.
// Write the body of `sqr_array` using the given helper function
// `_inner_sqr_array` and check that the program output
// is 1, 4, 9, 16.
// `sqr_array` should allocate the new array it returns.

// Use the output builtin.
%builtins output

from starkware.cairo.common.alloc import alloc
from starkware.cairo.common.serialize import serialize_word

// Fills `new_array` with the squares of the first `length` elements in `array`.
func _inner_sqr_array(array: felt*, new_array: felt*, length: felt) {
    if (length == 0) {
        return ();
    }

    assert [new_array] = [array] * [array];

    _inner_sqr_array(array=array + 1, new_array=new_array + 1, length=length - 1);
    return ();
}

func sqr_array(array: felt*, length: felt) -> (new_array: felt*) {
    // Write your code here.
}

func main{output_ptr: felt*}() {
    alloc_locals;
    // Allocate a new array.
    let (local array) = alloc();
    // Fill the new array with field elements.
    assert [array] = 1;
    assert [array + 1] = 2;
    assert [array + 2] = 3;
    assert [array + 3] = 4;

    let (new_array) = sqr_array(array=array, length=4);
    serialize_word([new_array]);
    serialize_word([new_array + 1]);
    serialize_word([new_array + 2]);
    serialize_word([new_array + 3]);

    return ();
}
```

---

> Answers to this question are a part of the ✨ 17 days of Cairo Lang with Playground & Newton. ✨
> 

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Newton-550dfcda6a2d449ca468be293c776578)*

How can I use dynamic allocation in Cairo? 

anyone has a function that converts an array of felts (numbers) to a single string in JS?

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Do you know a function that converts an array of felts (numbers) to a single string in JS? [Cairo Lang]

How large can addresses be in Cairo?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/670)_

How large can addresses be in Cairo?

Hello! I was wondering whether it was possible to check if a certain address has code in Cairo.
In Solidity, we do something like:

```
assembly {
  codeSize := extcodesize(contractAddress)
}
or just:
uint256 codeSize = contractAddress.code;
```
I was wondering if there was a way to check something like this in cairo? I checked the syscalls file but didn't find anything promising there.

Thank you in advance!

How to check if a contract has been deployed at a certain address in cairo?

If not, are there any workarounds?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/936)_

Does Cairo support int256, or negative numbers in general? 

Hey everyone, is it possible to use argentx to sign in/authenticate user to a off-chain api/db

What I want to do is store some data off chain for each user(wallet)

I have seen that metamask/etherem has 'personal_sign' rpc method that can be used for something like this

Is there anything like this available in starknet ecosystem?

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Is it possible to use ArgentX to sign in user to a off-chain api/db?

Why will I use events in the Cairo language? Can I use it on a front-end client application side?

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An error “AssertionError: Sender must be passed explicitly when making a direct declaration using —no_wallet.” using the new nile?

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