get_caller_address returning 0 on Devnet

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

Newton

Hey guys, has anyone had `get_caller_address` problems in devnet ? I feel like it's returning address 0 when it shouldn't so I made this small contract to test it

```%lang starknet

from starkware.cairo.common.cairo_builtins import HashBuiltin

from starkware.starknet.common.syscalls import (get_caller_address)


func caller_addr() -> (res: felt) {
}



func fn_to_be_called{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr: felt}() {
    let (caller) = get_caller_address();
    caller_addr.write(caller);    

    return ();
}


func get_caller_addr{syscall_ptr: felt*, pedersen_ptr: HashBuiltin*, range_check_ptr: felt}() -> (caller_addr: felt) {
    let (caller) = caller_addr.read();

    return (caller_addr=caller);
}```

and indeed `get_caller_addr` return address 0 after I called `fn_to_be_called` in the devnet. This is causing some problems in more complex contracts of course. Is it just me ?



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

Has anyone had `get_caller_address` problems in devnet ?

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The following code:



```
func pow4(n) -> (m : felt):
    alloc_locals
    local x

    jmp body if n != 0
    [ap] = 0; ap++
    ret

    body:
    x = n * n
    [ap] = x * x; ap++
    ret
end

func main():
    pow4(n=5)
    ret
end

```

is declared inefficient in the [doc](https://starknet.io/docs/how_cairo_works/consts.html#id7) because of non-continuous memory.


I ran it and could not see any hole in the memory table:



```
Addr  Value
-----------
â‹®
###
â‹®
1:0   2:0
1:1   3:0
1:2   5
1:3   1:2
1:4   0:21
1:5   25
1:6   625

```

so I don't understand where the problem is. I do see a hole with `n=0` though:



```
Addr  Value
-----------
â‹®
###
â‹®
1:0   2:0
1:1   3:0
1:2   0
1:3   1:2
1:4   0:21
â‹®
1:6   0

```

that I can fix using:



```
    jmp body if n != 0
    x = 0
    ret

```

but it's not what's suggested:


* Move the instruction alloc\_locals.
* or Use tempvar instead of local.



ㅤ
_This question was originally posted on [Stack Overflow](https://stackoverflow.com/questions/72601235/what-is-the-inefficiency-in-this-cairo-code-using-alloc-locals)_

What is the inefficiency in this cairo code using alloc_locals

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

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I am asking because I haven't the support of sha256 on [Github](https://github.com/NethermindEth/warp)

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why does keccak256 replace sha256 in warp?

Hello guys, i was wondering what are the projects on starknet that plan to do the domain .stark  plz

I know there is starknet id, but is there any others ?

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

What are the projects on starknet that plan to do the domain .stark?


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