Use the following recursive function to get the result you are looking for 


`func squared_summation(felt_array : felt*, felt_array_size : felt) -> (res : felt):`


 `if felt_array_size == 0:`


 `return (0)`


 `end`


 `let sum : felt = squared_summation(felt_array + 1, felt_array_size - 1)`


 `return (sum + [felt_array] * [felt_array])`


`end`


ㅤ
_This answer was originally posted on [Triality](https://triality.org/question/399)_

Given an array of elements [2,3,4] I want to be able to get the squared summation of the individual elements, 2^2 + 3^2 + 4^2.


How can I achieve this?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/399)_

Cairo: Getting the squared summation of felts in an array

How to verify Empiric’s Data Entries Using Events?

Hi team. How can I use start_prank with deploy_contract? Since get_caller_address() works in constructor now, I need a way in protostar to set caller address without having contract address. May be a 'caller' argument in deploy_contract cheatcode works best.

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

How can I use start_prank with deploy_contract? 

Hey! The title sort of summarizes the question. I was wondering if there's any project where I can see an example of how something like `keccak256(abi.encodePacked(var1, var2, var3))`  could be achieved in starknet.

If there were a way to concatenate bytes, I think it wouldn't be too complicated, but such a string would never fit in a felt, and using a struct won't result in the same output.

So yes, my question is if there's an equivalent way to achieve this behavior in cairo.

Equivalent to Solidity's keccak256(abi.encodePacked())?

I have a switch statment where I need to set two distinct, values so thought I would use a tuple  or a struct but I keep getting:

For a struct

`Expected a 'felt' or a pointer type. Got:<TYPE PATH> `

For a tuple

`Expected a 'felt' or a pointer type. Got:(felt,felt) `

This is with the unset tempvar being declared before the branching, and being set in each of the paths. 


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

A switch statement in Cairo lang to set two distinct values

hi guys! is it possible to import local python files into hints?

Like so:
```python
# Cairo here

%{
	import my_python_file.py
	# Python here
%}
```

Is it possible to import local python files into hints?

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

Hello, I deployed my contract using Argent X.
I click on "Developer settings" and then "Smart contract developement". I declare and deploy the contract.
Also used [this guide](https://www.newton.so/view/63a1890e581919f84b2a4c51) and it helped me.

But the contract is not automatically verified on starkscan or voyager. What should I do to get verified?

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Cairo: Getting the squared summation of felts in an array

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