Receiving Ether in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to make the contract able to receive Ether.

Blockchain / Solidity

contract ReceiveEther {
    receive() external payable [1] {
        // Function to receive Ether
    }
}

Drag options to blanks, or click blank then click option'

Apublic payable {}

B{}

Cexternal {}

Dpayable {}

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the payable keyword

Using public instead of external

Leaving the function body empty without braces

The receive function must be marked payable to accept Ether.

2fill in blank

medium

Complete the fallback function to receive Ether when no other function matches.

Blockchain / Solidity

contract ReceiveEther {
    fallback() external [1] {
        // fallback function
    }
}

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Aview

Bpublic

Cpayable

Dpure

Attempts:

3 left

💡 Hint

Common Mistakes

Not marking fallback as payable

Using view or pure which disallow state changes

The fallback function must be marked payable to accept Ether.

3fill in blank

hard

Fix the error in the receive function to correctly accept Ether.

Blockchain / Solidity

contract ReceiveEther {
    receive() external [1] {
        // receive Ether
    }
}

Drag options to blanks, or click blank then click option'

Apayable

Bpayable view

Cpure

Dview

Attempts:

3 left

💡 Hint

Common Mistakes

Adding view or pure modifiers

Omitting payable keyword

The receive function must be external payable without view or pure modifiers.

4fill in blank

hard

Fill both blanks to create a receive function that accepts Ether and emits an event.

Blockchain / Solidity

contract ReceiveEther {
    event Received(address sender, uint amount);

    receive() external [1] {
        emit Received(msg.sender, msg.value[2]);
    }
}

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Apayable

Bpublic

C+

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using public instead of payable

Using multiplication instead of addition in event emit

The receive function must be payable and the event emits msg.value as is, so the plus sign is correct to complete the expression.

5fill in blank

hard

Fill both blanks to create a fallback function that accepts Ether, updates balance, and emits an event.

Blockchain / Solidity

contract ReceiveEther {
    mapping(address => uint) public balances;
    event Received(address sender, uint amount);

    fallback() external [1] {
        balances[msg.sender] [2] msg.value;
        emit Received(msg.sender, balances[msg.sender]);
    }
}

Drag options to blanks, or click blank then click option'

Apayable

B+=

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Not marking fallback payable

Using = instead of += for balance update

Adding operators after balances[msg.sender] in event

The fallback function must be payable. Use += to add the received Ether to the sender's balance. The event emits the updated balance, so no extra operator is needed.