Sending Ether (transfer, send, call) in Blockchain / Solidity - Mini Project: Build & Apply

Sending Ether (transfer, send, call)

📖 Scenario: You are creating a simple smart contract on Ethereum that can send Ether to another address. You will learn three ways to send Ether: transfer, send, and call. This is important for handling payments or sending funds securely.

🎯 Goal: Build a Solidity contract named EtherSender that can send Ether to a recipient address using transfer, send, and call methods. You will set up the contract, add a recipient address, implement the sending functions, and finally test sending Ether.

📋 What You'll Learn

Create a payable contract named EtherSender

Add a public address variable called recipient

Add a function to set the recipient address

Implement three functions to send Ether using transfer, send, and call

Add a function to receive Ether into the contract

Print or return success status for send and call methods

💡 Why This Matters

🌍 Real World

Sending Ether is a core operation in Ethereum smart contracts for payments, refunds, and transfers between users or contracts.

💼 Career

Understanding how to safely send Ether using transfer, send, and call is essential for blockchain developers to build secure and reliable decentralized applications.

1

Create the contract and recipient address

Create a Solidity contract named EtherSender. Inside it, declare a public address variable called recipient to store the address that will receive Ether.

Blockchain / Solidity

contract EtherSender {
    // Your code here
}

Need a hint?

Use contract EtherSender {} to start. Declare address public recipient; inside.

2

Add a function to set the recipient address

Add a public function named setRecipient that takes an address parameter called _recipient and sets the contract's recipient variable to this value.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract EtherSender {
    address public recipient;

    // Your code here
}

Need a hint?

Write a function setRecipient with parameter address _recipient. Inside, assign recipient = _recipient;.

3

Implement functions to send Ether using transfer, send, and call

Add three public payable functions: sendViaTransfer, sendViaSend, and sendViaCall. Each function should send the Ether sent to the contract to the recipient address using the respective method. For sendViaSend and sendViaCall, return a bool indicating success.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract EtherSender {
    address public recipient;

    function setRecipient(address _recipient) public {
        recipient = _recipient;
    }

    // Your code here
}

Need a hint?

Use payable(recipient).transfer(msg.value); in sendViaTransfer. For sendViaSend, use bool sent = payable(recipient).send(msg.value); return sent;. For sendViaCall, use (bool sent, ) = payable(recipient).call{value: msg.value}(""); return sent;.

4

Add a receive function and test sending Ether

Add a receive external payable function to allow the contract to accept Ether. Then add a public view function named getBalance that returns the contract's Ether balance. Finally, print the balance after sending Ether using any of the sending functions.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract EtherSender {
    address public recipient;

    function setRecipient(address _recipient) public {
        recipient = _recipient;
    }

    function sendViaTransfer() public payable {
        payable(recipient).transfer(msg.value);
    }

    function sendViaSend() public payable returns (bool) {
        bool sent = payable(recipient).send(msg.value);
        return sent;
    }

    function sendViaCall() public payable returns (bool) {
        (bool sent, ) = payable(recipient).call{value: msg.value}("");
        return sent;
    }

    // Your code here
}

Need a hint?

Add receive() external payable {} to accept Ether. Add getBalance() to return address(this).balance.