Creating custom Ethereum token

Question

I want to create my own Eth token, using Ethereum wallet and the code from this simple tutorial given in the ethereum.org website.

I don't have a programming background, knowing only basic info about JS and need a lot of help.

Custom ETH tokens are used, for example, as ICO to fund tech-based teams. If I understand correctly, when a certain address receives ETH (sent by a person to an ICO), the "contract" made by this ICO sends him back a portion of the custom tokens.

Is this present in the code below? How can I edit the "ratio" between ETH and the custom token (example: you send 1 ETH and receive 588 c.tokens - ratio 1:588)?

 pragma solidity ^0.4.8; contract tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData); } contract MyToken { /* Public variables of the token */ string public standard = 'Token 0.1'; string public name; string public symbol; uint8 public decimals; uint256 public totalSupply; /* This creates an array with all balances */ mapping (address => uint256) public balanceOf; mapping (address => mapping (address => uint256)) public allowance; /* This generates a public event on the blockchain that will notify clients */ event Transfer(address indexed from, address indexed to, uint256 value); /* This notifies clients about the amount burnt */ event Burn(address indexed from, uint256 value); /* Initializes contract with initial supply tokens to the creator of the contract */ function MyToken( uint256 initialSupply, string tokenName, uint8 decimalUnits, string tokenSymbol ) { balanceOf[msg.sender] = initialSupply; // Give the creator all initial tokens totalSupply = initialSupply; // Update total supply name = tokenName; // Set the name for display purposes symbol = tokenSymbol; // Set the symbol for display purposes decimals = decimalUnits; // Amount of decimals for display purposes } /* Send coins */ function transfer(address _to, uint256 _value) { if (_to == 0x0) throw; // Prevent transfer to 0x0 address. Use burn() instead if (balanceOf[msg.sender] < _value) throw; // Check if the sender has enough if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows balanceOf[msg.sender] -= _value; // Subtract from the sender balanceOf[_to] += _value; // Add the same to the recipient Transfer(msg.sender, _to, _value); // Notify anyone listening that this transfer took place } /* Allow another contract to spend some tokens in your behalf */ function approve(address _spender, uint256 _value) returns (bool success) { allowance[msg.sender][_spender] = _value; return true; } /* Approve and then communicate the approved contract in a single tx */ function approveAndCall(address _spender, uint256 _value, bytes _extraData) returns (bool success) { tokenRecipient spender = tokenRecipient(_spender); if (approve(_spender, _value)) { spender.receiveApproval(msg.sender, _value, this, _extraData); return true; } } /* A contract attempts to get the coins */ function transferFrom(address _from, address _to, uint256 _value) returns (bool success) { if (_to == 0x0) throw; // Prevent transfer to 0x0 address. Use burn() instead if (balanceOf[_from] < _value) throw; // Check if the sender has enough if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows if (_value > allowance[_from][msg.sender]) throw; // Check allowance balanceOf[_from] -= _value; // Subtract from the sender balanceOf[_to] += _value; // Add the same to the recipient allowance[_from][msg.sender] -= _value; Transfer(_from, _to, _value); return true; } function burn(uint256 _value) returns (bool success) { if (balanceOf[msg.sender] < _value) throw; // Check if the sender has enough balanceOf[msg.sender] -= _value; // Subtract from the sender totalSupply -= _value; // Updates totalSupply Burn(msg.sender, _value); return true; } function burnFrom(address _from, uint256 _value) returns (bool success) { if (balanceOf[_from] < _value) throw; // Check if the sender has enough if (_value > allowance[_from][msg.sender]) throw; // Check allowance balanceOf[_from] -= _value; // Subtract from the sender totalSupply -= _value; // Updates totalSupply Burn(_from, _value); return true; } }

Answer 1

1) get amount of custom token (msg.value/ratioAmount)

2) transfer that amount to the requester

you have to use a payable fallback function in which you should call a function which will be dealing with above two mentioned activities.

Send() will invoke payable fallback function which in turn call your custom function which will be doing the actual work.

Check fallback function in solidity documentation.

payable is necessary for send() after DAO incident.