06_5aa0a942ec25_SmartBank.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

contract SmartBank {
    mapping (address => uint) public balances;
    
    function deposit() public payable {
        balances[msg.sender] = msg.value;
    }
    
    function withdraw(uint amount) public {
        require(amount <= balances[msg.sender], "Your balance is not enough!");
        
        payable(msg.sender).transfer(amount);
        balances[msg.sender] -= amount;
    }
    
    function transfer(uint amount, address payable destAddr) public {
        require(amount <= balances[msg.sender], "Your balance is not enough!");
        balances[msg.sender] -= amount;
        balances[destAddr] += amount;
    }
}