Reputation: 2263
pragma solidity ^0.4.18;
contract Voting {
address mainAddress;
bytes32[] candidateNames;
mapping(bytes32 => uint) candidateVotes;
mapping(bytes32 => bytes32) candidatesDetails;
address[] voters;
function Voting() public {
mainAddress = msg.sender;
}
modifier isMainAddress {
if (msg.sender == mainAddress) {
_;
}
}
function getAllCandidates() public view returns (bytes32[]) {
return candidateNames;
}
function setCandidate(bytes32 newCandidate) isMainAddress public {
candidateNames.push(newCandidate);
}
function setVote(bytes32 candidate) public {
require(validVoters());
candidateVotes[candidate] = candidateVotes[candidate] + 1;
voters.push(msg.sender);
}
function getVote(bytes32 candidate) public view returns (uint) {
return candidateVotes[candidate];
}
function setDescrption(bytes32 candidateName, bytes32 candidatesDesc) isMainAddress public {
candidatesDetails[candidateName] = candidatesDesc;
}
function getDescription(bytes32 candidateName) public view returns (bytes32){
return candidatesDetails[candidateName];
}
function getCurrentAddress() public view returns (address) {
return msg.sender;
}
function validVoters() public view returns (bool) {
for(uint i = 0; i < voters.length ; i++){
if (voters[i] == msg.sender) {
return false;
}
}
return true;
}
}
The functions : Voting(), getAllCandidates(), setCandidate(), getVote(), setDescription(), getDescription(), getCurrentAddress() works fine when called multiple times. So, I guess we can ignore them for now.
The function setVote() runs fine the first time it executes ie. when a person votes for once. The problem arises when the same person tries to vote the second time. It gives the following error :
This might be a beginners mistake but I have been trying to fix this for 2 days straight and now I really need help.
Also,
I use Remix - browser based IDE to run/check my solidity code.
I use Ganache for test accounts.
Thanks.
Upvotes: 0
Views: 417
Reputation: 60153
The function in question:
function setVote(bytes32 candidate) public {
require(validVoters());
candidateVotes[candidate] = candidateVotes[candidate] + 1;
voters.push(msg.sender);
}
Note that validVoters()
must return true
for this function to succeed. If it returns false
, the require
will fail and revert the transaction. Also note that at the end of the function, msg.sender
is added to the array voters
.
Let's take a look at validVoters()
:
function validVoters() public view returns (bool) {
for(uint i = 0; i < voters.length ; i++){
if (voters[i] == msg.sender) {
return false;
}
}
return true;
}
This function returns false
if msg.sender
is in voters
, which we know will be the case after the account has voted once.
So the second time through, validVoters()
returns false
, which causes require(validVoters())
in setVote()
to revert the transaction.
Upvotes: 2