Jul 25, 2024
pragma solidity ^0.8.25;
contract HelloWorld {
function hello() public pure returns (string memory) {
return 'Hello, World!';
}
}
contract: Keyword for defining a contractuint public var1 = 10;
uint private var2;
function increment() public {
data += 1;
}
function decrement() public {
data -= 1;
}
function deposit() external payable {}
function withdraw(address payable to, uint amount) external {
to.transfer(amount);
}
uint[] public balances;
function addBalance(uint value) public {
balances.push(value);
}
function getBalance(uint index) public view returns (uint) {
return balances[index];
}
mapping(address => uint) public balances;
function setBalance(address addr, uint value) public {
balances[addr] = value;
}
function getBalance(address addr) public view returns (uint) {
return balances[addr];
}
address public owner;
constructor() {
owner = msg.sender;
}
function onlyOwner() public view returns(bool) {
return msg.sender == owner;
}
function withdraw(uint amount) public {
require(msg.sender == owner, 'Only owner');
msg.sender.transfer(amount);
}
struct User {
uint balance;
string name;
uint joinDate;
}
mapping(address => User) public users;
function createUser(address userAddr, uint balance, string memory name) public {
users[userAddr] = User(balance, name, block.timestamp);
}
function getUser(address userAddr) public view returns (User memory) {
return users[userAddr];
}