Data structures · easy

5. Mappings

Key/value storage.

Build a `Balances` contract with `mapping(address => uint256) public balances` and a `deposit()` payable function that credits `msg.value`.

Required in your answer: mapping(address => uint256) public balancesbalances[msg.sender] += msg.valuepayable

Compiles with solc in your browser

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Balances {
    // TODO mapping
    function deposit() external payable {
        // TODO
    }
}

Output appears here.

← 4. Addresses & msg.sender 6. Dynamic Arrays →