Undeclared identifier when compiling with truffle compile

Question

I have this contract and can't figure out where's the problem. Any ideas? (I'm a noob in solidity, just started a few days ago).

HelloWorld.sol file:

mapping (address => uint) balances;

function HelloWorld() {
    balances[msg.sender] = 1000;
}

function getBalance() public constant returns(uint) {
    return balances;
}

function sendCoin(address receiver, uint amount) public constant returns(bool sufficient) {
    if (balances[msg.sender] < amount) return false;

    balances[msg.sender] -= amount;
    balances[receiver] += amount;
    return true;
}

Moon.sol file:

mapping (address => uint) balances;

function Moon () {
    balances[tx.origin] = 1000;
}   

function getBalance() public constant returns(uint) {
    return balances;
}

In the Moon.sol file I missed out "mapping (address => uint) balances;".

Truffle compiler error:

$ truffle compile
Compiling .\contracts\HelloWorld.sol...
Compiling .\contracts\Moon.sol...

/C/Users/guerr/SmartContracs/firstPorject/contracts/Moon.sol:10:3: : 
Undeclared identifier.
            balances[tx.origin] = 1000;
            ^------^
Compiliation failed. See above.

Answer 1

Your code looks okay but you should change tx.origin to msg.sender for security reasons. tx.origin is almost always an error.

I would get rid of that moon.sol file and try again.