Accessing function in Truffle console

Question

I'm running a simple Solity contract which can hold it's own balances for users however I cannot seem to run the transfer function

pragma solidity ^0.4.8;

contract SimpleWallet {

    address public owner;
    mapping (address => uint) balances;

    // Constructor
    function SimpleWallet(){
        owner = msg.sender;
        balances[owner] = 1000;
    }

    function transfer(address _to, uint _value) returns (bool success){
        if (balances[msg.sender] < _value) {
            return false;
        }

        balances[msg.sender] -= _value;
        balances[_to] += _value;
        return true;
    }

    function getBalance(address _user) constant returns (uint _balance) {
        return balances[_user];
    }
}

I'll then run..

x = SimpleWallet.deployed()

a1 = web3.eth.accounts[0]

x.then(i => i.getBalance(a1).then(console.log))

And get a returned error

Error: Error: VM Exception while executing eth_call: invalid JUMP at f05bf9ee42d946231b79045ab38aabe852ea0113d27e047820c05041e8c24734/7be97c83604dc80e217456e9da80bc0a2d73f847:43
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/web3-provider-engine/subproviders/vm.js:117:17
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/lib/runTx.js:59:5
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:3824:9
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:460:16
    at replenish (/usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:977:25)
    at iterateeCallback (/usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:967:17)
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:944:16
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:3821:13
    at apply (/usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:21:25)
    at /usr/local/lib/node_modules/ethereumjs-testrpc/node_modules/ethereumjs-vm/node_modules/async/dist/async.js:56:12
    at Object.module.exports.InvalidResponse (/usr/local/lib/node_modules/truffle/node_modules/web3/lib/web3/errors.js:35:16)
    at /usr/local/lib/node_modules/truffle/node_modules/web3/lib/web3/requestmanager.js:86:36
    at XMLHttpRequest.request.onreadystatechange (/usr/local/lib/node_modules/truffle/node_modules/web3/lib/web3/httpprovider.js:118:13)
    at XMLHttpRequestEventTarget.dispatchEvent (/usr/local/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:64:18)
    at XMLHttpRequest._setReadyState (/usr/local/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:354:12)
    at XMLHttpRequest._onHttpResponseEnd (/usr/local/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:509:12)
    at IncomingMessage.<anonymous> (/usr/local/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:469:24)
    at emitNone (events.js:91:20)
    at IncomingMessage.emit (events.js:185:7)
    at endReadableNT (_stream_readable.js:975:12)

Answer 1

This is how you can access/call function in truffle console.

$ truffle console

truffle(development)> compile
truffle(development)> contract_name.new('Constructor Initialization')

// Above command will return lot of things on console, second last 
// attribute would be address(hash of the contract)
// use it the next line of command

truffle(development)> contract_name.at("contract address").functionName()

Hope this helps.

Answer 2

After deployed using truffle,

x = SimpleWallet.deployed()

you can then call functions,

var balance =x.getBalance(a)

Answer 3

Simply open the Truffle console with the given command : $truffle console

and make an instance of the contract

var instance_name = ContractName.at(Contract_Address)

Contract_Address can be accessed simply by writing : ContractName.address

When the instance got created, use it to call the functions in the smart contract like :

instance_name.function_name(...)