
```
%builtins output

from starkware.cairo.common.serialize import serialize_word

func main{output_ptr: felt*}() {
    print(4, 100, 100);
    return ();
}

func print{output_ptr: felt*}(times: felt, start, step: felt){
    if(times == 0){
        return();
    }
    serialize_word(start);
    print(times-1, start+step, step);
    return();
}
```


Can you help how to change the code so that it outputs 400 as well?

```
// The following code outputs the numbers 100, 200, 300.
// 1. Click on "Run" to see the output.
// 2. Change it to output 400 as well.

// Use the output builtin.
%builtins output

// Import the serialize_word() function.
from starkware.cairo.common.serialize import serialize_word

func main{output_ptr: felt*}() {
// Output 100 by calling serialize_word.
serialize_word(100);
// Output 200.
serialize_word(200);
// Output 300.
serialize_word(300);
// Return.
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-Playground-Newton-550dfcda6a2d449ca468be293c776578)*

How to make output like "hello world" in Cairo Language (StarkNet)?

Account and declare code look fine. I can see two possible issues: 
The first one is an issue with reading the JSON contract file and the second one is a mismatch in the Account - Key Pair.

It is good practice to run devnet with a flag 
```
-seed 0
```
 so that we can reproduce the same account and key.

This is how we parse json

```
  json.parse(
    fs.readFileSync(path.resolve(__dirname, `../__mocks__/${name}.json`)).toString('ascii')
  );
```
json needs to support bigint we use 

```
'json-bigint'
```

[https://github.com/0xs34n/starknet.js/blob/develop/src/utils/json.ts](https://github.com/0xs34n/starknet.js/blob/develop/src/utils/json.ts)


Hey! With starknetjs(4.15.1) I am trying to declare a contract on devnet(0.4.2) using one of  predeployed accounts:

```
const account = new Account(
  provider,    '0x33507ff2edf12c12c73d0b6d1d90de9fac12a355de1097ab305249612451919',
  ec.getKeyPair('0x1de9ea6670d3da1fc735df5ef7697fb9')
);
...
const response = await account.declare({contract, classHash})
```

In return I get:

```
     GatewayError: Error at pc=0:124:
Signature (190318159909676960154007463740407923762489366165178197276822367516441018681, 1481560316189074241501727945883196969140908548840364106059171525936237675551), is invalid, with respect to the public key 1739835831186746845112715264902076958080619051586179661985458614041125785393, and the message hash 1015445806423683747697120201561835375586563571781789449937604429244570518935.
Cairo traceback (most recent call last):
Unknown location (pc=0:615)
Unknown location (pc=0:600)
Unknown location (pc=0:245)
```


Popular tags

Profile

Toni Tabak

Wallet address: 0x0360D2E7A038388D6DAdcaD933Ef0881550FcD75

Recent questions

Recent answers