Hi here's the StarkEx Playground Tutorial you can refer to
https://docs.starkware.co/starkex/starkex_playground_tutorial.html

StarkNet is a permissionless decentralized ZK-Rollup that supports independent deployment of smart contracts. Any developer can write and deploy their smart contract permissionlessly. StarkNet also supports composability.
StarkEx is a permissioned tailor-made scaling engine, designed by StarkWare to fit the specific needs of apps.


And for more details on starkex, pls check this article: https://medium.com/starkware/starks-starkex-and-starknet-9a426680745a 

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

Newton

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?

>Hello! This is day 5 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 “Revoked references”. Can you run these 6 steps and write down what you see?

```
// The scope of some types of references in Cairo (e.g., return values of
// functions and temporary variables) is somewhat restricted.
// For example, a call to another function may revoke those references.
//
// 1. Try to run the following code. You should get an error that `x` was revoked
//    (this is because of the second call to `foo`).
// 2. In simple cases, like this one, the compiler can solve this automatically
//    if the "alloc_locals" keyword is used within the function's scope.
//    Add "alloc_locals;" to the beginning of main(), and make sure the code works.
// 3. To understand what happens behind the scenes, replace "alloc_locals;" with
//    "ap += SIZEOF_LOCALS;" - this command allocates memory cells for local variables
//    (you'll need them below) but doesn't enable the mechanism that
//    automatically resolves revoked references.
//    Trying to run the code now should result in the original error.
// 4. Solve the problem manually by copying the value of `x` to a local variable
//    (e.g., "local x2 = x;"). Local variables are not revoked when functions
//    are called.
//    You can read more about local variables [here](https://www.cairo-lang.org/docs/how_cairo_works/consts.html#local-vars).
// 5. You can even use the same name: "local x = x;".
//    This is called "reference rebinding", where the meaning of `x` changes:
//      Before this line, `x` refers to the return value.
//      After that, `x` refers to the local variable.
// 6. A shorter syntax is "let (local x) = foo(10);" which achieves the same goal.
//    Try it!

%builtins output

from starkware.cairo.common.serialize import serialize_word

// Returns a^3 for a != 0 and 1 otherwise.
func foo(a) -> (res: felt) {
    if (a == 0) {
        return (res=1);
    } else {
        return (res=a * a * a);
    }
}

// Outputs the value 10^3 + 5^3.
func main{output_ptr: felt*}() {
    let (x) = foo(10);
    let (y) = foo(5);
    serialize_word(x + y);
    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)*



Cairo Lang / StarkNet: What are Revoked references? What is alloc_locals?

What are multi-calls in Account Abstraction? What will it bring to the UX?

How do I put funds into my newly created account from the ape console?


ApeWorX: How do I fund newly created accounts from the ape console?

Hey, is there anyway to debug Cairo contracts in hardhat environment? Something like hardhat console in Solidity?

Hey, is there anyway to debug Cairo contracts in hardhat environment? Something like hardhat console in solidity

I'm very curious: does Cairo have any logic operators? I found bitwise_or bitwise_and etc. but it is not wokring if I want to do something like

if (x == y) OR (x == -y) { ... }

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

Does Cairo Lang have any logic operators?

What will the bundler ecosystem look like in AA?

---

This question is participating in [Newton Bounties | Incentivized Test Program](https://www.notion.so/Newton-Bounties-Incentivized-Test-Program-94322ad48e7d40a3adcf36f6b26174cd) Every verified valid question gets $10 USDC (mainnet)

What will the bundler ecosystem look like in Account Abstraction?

## What is Kakarot, the zkEVM written in Cairo?


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