At this moment there is not any console logging. It is not possible to make a function

```
func main(y: felt) {
    // print value of y here
}

```
in Cairo 1

Newton

I have a question about how to print "Hello World" in Cairo 1. How do I log/print ?

How do I log/print in Cairo 1.0?

Hello! This is day 15 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 “SHARP”.  Perhaps you can help me?

```
// The program below lets you choose a number `x` and output its square `y = x*x`
// (proving that you know the square root of `y`).
//
// 1. Replace "YOUR_NUMBER" with a value of your choice, run the program and
//    make sure you get the expected output (the square of the value you chose).
//
// Take a look at the output line saying "Program hash: ...".
// The program hash is the (Pedersen) hash of the compiled program.
//
// 2. The compiled program does not include the [hints](https://cairo-lang.org/docs/how_cairo_works/hints.html),
//    so changing any code within a hint does not change the resulting program
//    hash.
//    Try changing `x` to a different number and note that the program hash remains
//    unchanged after rerunning.
//
// The Cairo SHARP collects several programs and creates a proof that they ran
// successfully. Such a batch of programs is called a "train".
// Note that it may take a while until a train is created, as the service waits
// to collect enough programs (after a certain amount of time, the train will
// be dispatched, even if it's not full).
//
// 3. Click on "Prove with SHARP" to prove the program using the shared proving service.
//
// After the proof is created, SHARP sends it to an [Ethereum goerli contract](https://goerli.etherscan.io/address/0xAB43bA48c9edF4C2C4bB01237348D1D7B28ef168).
// For each job in the train, a corresponding fact is registered on the contract,
// attesting to the validity of the run with its particular output.
//
// 4. You can monitor the status of your job, using the link in the output pane.
//
// For each job, the corresponding fact is computed as follows:
//   keccak(program_hash, keccak(program_output))
// where:
// * program_hash is the hash of the compiled program, which you can find in
//   the output pane (32 bytes).
// * program_output is the output of the program as a list of 32-byte
//   elements.
//
// For example, if you chose x=3, the output will be [9] and you can compute
// the fact in Python using:
//
//   from web3 import Web3
//
//   program_hash = 0x114952172aed91e59f870a314e75de0a437ff550e4618068cec2d832e48b0c7
//   program_output = [9]
//   Web3.solidityKeccak(['uint256', 'bytes32'], [
//     program_hash,
//     Web3.solidityKeccak(['uint256[]'], [program_output])
//   ])
//
// You can also find your job's fact in the SHARP tracking page you opened
// in step 4.
//
// 5. Once you see that the fact is registered, you can call the
//    [contract's isValid() method](https://goerli.etherscan.io/address/0xAB43bA48c9edF4C2C4bB01237348D1D7B28ef168#readContract) to make sure it's indeed registered.

%builtins output

from starkware.cairo.common.serialize import serialize_word

func main{output_ptr: felt*}() {
    alloc_locals;
    local x;
    %{ ids.x = YOUR_NUMBER %}

    serialize_word(x * x);
    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)*

What is SHARP in Cairo Language?

Hello! This is day 14 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 “Hints”.  Perhaps you can help me?

```
// The following function uses hints to efficiently compute the square root `res`
// of the argument `n`.
// The idea is that the verifier only needs to be convinced that res * res = n,
// it doesn't really care how res was computed.
// In such cases, we don't have to compute res in pure Cairo - we can write a
// piece of Python code inside the Cairo program, which is called a "hint".
// A hint is a piece of code that the prover runs to initialize
// some memory cells. Note that it is completely transparent from the verifier's
// point of view, so the result of the hint *must* be verified using pure Cairo
// instructions (e.g., the "assert n = res * res" instruction below).
//
// 1. Comment out the line "assert n = res * res;" and run the code. Does it still output
//    the expected value? Can you explain why the assert is nonetheless essential?
//    Hint: Recall that from the verifier's point of view, the hint does not exist.
// 2. Uncomment the assert line and change the function to compute the fourth
//    root.

%builtins output

from starkware.cairo.common.serialize import serialize_word

// Computes the square root (over the integers) of `n`.
// Prover assumption: The square root exists.
func sqrt(n) -> (res: felt) {
    alloc_locals;
    local res;

    // Set the value of res using a Python hint.
    %{
        import math

        # Use the ids variable to access the value of a Cairo variable.
        ids.res = int(math.sqrt(ids.n))
    %}

    // From the verifier's point of view, the hint is completely transparent.
    // The following line guarantees that `res` is the square root
    // (either the positive or negative) of `n`.
    assert n = res * res;
    return (res=res);
}

func main{output_ptr: felt*}() {
    let (res) = sqrt(256);
    serialize_word(res);
    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 to use Hints in Cairo Lang?

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 ?

How to transpile multiple contracts at once using [Nethermind's warp](https://github.com/NethermindEth/warp)?

How to transpile multiple contracts at once using warp?

Python issues with Pathfinder

Hello, I am trying to implement the connect wallet : ``` import { useConnectors } from '-react/core' function YourComponent() { const { connect, connectors } = useConnectors() return ( <div> {connectors.map((connector) => connector.available() ? ( <button key={connector.id()} onClick={() => connect(connector)}> Connect {connector.name()} </button> ) : null )} </div> ) } ``` I feel like connectors will only give the wallet if I have it on my chrome extensions , so whats the point of connector.available() ? I am using : ``` const connectors = getInstalledInjectedConnectors() ```

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

Implementing the connect wallet. Can you help about connectors?

Would really like to understand how a full node for Starknet like pathfinder works

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