msg.value and msg.sender in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the address of the caller.

Blockchain / Solidity

address caller = [1];

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Amsg.value

Baddress(this)

Ctx.origin

Dmsg.sender

Attempts:

3 left

💡 Hint

Common Mistakes

Using msg.value instead of msg.sender

Using tx.origin which is less secure

Using address(this) which is the contract's address

msg.sender holds the address of the caller who invoked the function.

2fill in blank

medium

Complete the code to get the amount of Ether sent with the call.

Blockchain / Solidity

uint amount = [1];

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Atx.gasprice

Bmsg.value

Cmsg.sender

Dmsg.gas

Attempts:

3 left

💡 Hint

Common Mistakes

Using msg.sender instead of msg.value

Using tx.gasprice which is gas price, not value

Using msg.gas which is deprecated

msg.value holds the amount of Ether (in wei) sent with the transaction.

3fill in blank

hard

Fix the error in the function to correctly check if Ether was sent.

Blockchain / Solidity

function deposit() public payable {
    require([1] > 0, "Send some Ether");
}

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Amsg.value

Btx.origin

Caddress(this).balance

Dmsg.sender

Attempts:

3 left

💡 Hint

Common Mistakes

Checking msg.sender instead of msg.value

Using address(this).balance which is total contract balance

The function must check msg.value to see if Ether was sent.

4fill in blank

hard

Fill both blanks to create a function that returns the sender and the amount sent.

Blockchain / Solidity

function getInfo() public view returns (address, uint) {
    return ([1], [2]);
}

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Amsg.sender

Bmsg.value

Ctx.origin

Daddress(this)

Attempts:

3 left

💡 Hint

Common Mistakes

Returning tx.origin instead of msg.sender

Returning address(this) instead of msg.sender

Returning msg.sender and tx.origin mixed

The function returns the caller's address (msg.sender) and the Ether sent (msg.value).

5fill in blank

hard

Fill all three blanks to create a payable function that stores sender and amount in state variables.

Blockchain / Solidity

address public lastSender;
uint public lastAmount;

function recordPayment() public payable {
    lastSender = [1];
    lastAmount = [2];
    emit PaymentReceived([3]);
}

event PaymentReceived(address sender);

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Amsg.sender

Bmsg.value

DlastSender

Attempts:

3 left

💡 Hint

Common Mistakes

Using lastSender instead of msg.sender in the event

Mixing up msg.sender and msg.value assignments

The function saves msg.sender and msg.value to state variables, then emits an event with the sender's address.