﻿[﻿](https://github.com/starkware-libs/cairo-lang/blob/54d7e92a703b3b5a1e07e9389608178129946efc/src/starkware/starknet/compiler/external_wrapper.py#L50-L65)You can see some of the decorators here: <https://github.com/starkware-libs/cairo-lang/blob/54d7e92a703b3b5a1e07e9389608178129946efc/src/starkware/starknet/compiler/external_wrapper.py#L50-L65>﻿


ㅤ
_This answer was originally posted on [Triality](https://triality.org/question/1075)_

Is there a list of this compiled somewhere? Thanks


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/1075)_

Where can I find a list of decorators available in Cairo?

hi, i used the starkgate bridge from stark to eth one hour ago. Withdrawal has not occurred yet. How many hours does the process take? My tx hash is: <address>cfa0c02d013658804505506

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

How many time does it take for stark to eth starkgate bridge process?

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? 

In the following function I am presented with the following error, even though my code does not make it to this function. What am I doing wrong?


`func fill_in_row{output_ptr: felt*}(row_idx : felt, row_size : felt, curr_row : felt*) {` 


 `if (row_idx == row_size-2) {`


 `return ();`


 `}`


 `let val : felt = curr_row[row_idx-1] + curr_row[row_idx];`


 `serialize_word(val);`


 `curr_row[row_idx+1] = val;`


 `return fill_in_row(row_idx+1, row_size, curr_row);`


`}`


Error: code:80:5: While expanding the reference 'curr_row' in:


 curr_row[row_idx+1] = val;


 ^******^


code:72:73: Expected a register. Found: [fp + (-4)].


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/1156)_

Cairo Error: Getting Error while setting value of item in array

hi all. If I want to use starkex do I have to deploy my custom starkex contracts ?
however in my understanding startex is a protocol where I have to intergrate my dapp specific tx, isn't it ?
in the playground I saw there're some preimplemented tx like ERC20 interface 
is starknet a starkex with an integrated VirtualMachine ?

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

If I want to use starkex do I have to deploy my custom starkex contracts?

Hey team, is the below legit ?https://odyssey.starknet.id/

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

Is starknet.id legit?

Hello, Starknet will do Final State Reset around Q4 2022.    It means users need to create new wallet address & migrate asset to new wallet.   Old wallet address will be no longer usable after final state reset.     Is this correct?

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

Will StarkNet wallets work after Q4 2022 Final State Reset? Or do I need to create and merge a new wallet?

I am currently running this code

```
func main() {

    let x = [ap];
    [ap] = 1, ap++;

    [ap] = 2, ap++;

    [ap] = x, ap++;
    jmp rel -1;  // Jump to the previous instruction.
}

And what is happening is that "x" is alternating between 1 and 2 and I couldn't figure out why.

Also, it wasn't very clear to me what a "Revoked Reference" means. Is it when you cannot access a certain [ap] when running a specific function?

This is the link to the exercise:
https://www.cairo-lang.org/docs/how_cairo_works/consts.html#revoked-references

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Where can I find a list of decorators available in Cairo?

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