nexto123

pragma solidity 0.7.5;
contract MemoryAndStorage {

    mapping(uint => User) users;

    struct User{
        uint id;
        uint balance;
    }

nexto123

pragma solidity 0.8.1;

contract Bank {
    
    mapping(address => uint) balance;
    
    function addBalance(uint _toAdd) public returns (uint) {
        
        balance[msg.sender] += _toAdd;