Multi-chain deployment in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a contract named "MultiChain".

Blockchain / Solidity

contract [1] {
    // contract code
}

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ADeployChain

BMultiChain

CMultiChainDeploy

DChainMulti

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different contract name that does not match the deployment context.

The contract name must match the intended name for clarity and deployment. "MultiChain" is the correct name here.

2fill in blank

medium

Complete the code to define a function that returns the current chain ID.

Blockchain / Solidity

function getChainId() public view returns (uint256) {
    return [1];
}

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Ablock.chainid

Bblock.number

Cmsg.sender

Dtx.origin

Attempts:

3 left

💡 Hint

Common Mistakes

Using block.number which returns the block height, not the chain ID.

Using msg.sender or tx.origin which relate to addresses, not chain info.

The block.chainid returns the current blockchain's chain ID, which is essential for multi-chain deployment.

3fill in blank

hard

Fix the error in the function that sets the chain-specific address mapping.

Blockchain / Solidity

mapping(uint256 => address) public chainAddresses;

function setAddress(uint256 chainId, address addr) public {
    chainAddresses[[1]] = addr;
}

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AchainId

BchainAddresses

Cmsg.sender

Daddr

Attempts:

3 left

💡 Hint

Common Mistakes

Using the address or the mapping itself as the key instead of the chain ID.

The mapping key should be the chainId parameter to correctly store the address for that chain.

4fill in blank

hard

Fill both blanks to complete the function that returns the address for the current chain.

Blockchain / Solidity

function getAddress() public view returns (address) {
    uint256 currentChain = [1];
    return chainAddresses[[2]];
}

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Ablock.chainid

Bmsg.sender

CcurrentChain

Dtx.origin

Attempts:

3 left

💡 Hint

Common Mistakes

Using msg.sender or tx.origin instead of the chain ID.

Using block.chainid directly in the return statement without storing it first.

The function first gets the current chain ID using block.chainid and then returns the address stored for that chain using the variable currentChain.

5fill in blank

hard

Fill all three blanks to complete the multi-chain deployment contract with initialization.

Blockchain / Solidity

contract MultiChain {
    mapping(uint256 => address) public chainAddresses;

    constructor(address [1]) {
        uint256 chainId = [2];
        chainAddresses[chainId] = [3];
    }
}

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AinitialAddress

Bblock.chainid

Dmsg.sender

Attempts:

3 left

💡 Hint

Common Mistakes

Using msg.sender instead of the passed address parameter.

Not using block.chainid to get the chain ID.

Mixing up variable names in the constructor.

The constructor takes an initialAddress parameter, gets the current chain ID with block.chainid, and sets the mapping for that chain to the initial address.