erc20-transfer.sol

contract MyERCToken {
  mapping(address => uint256) balances;
  
  // Note: This function returns a boolean value
  //       indicating whether the transfer was successful
  function transfer(address _to, uint256 _amount) returns (bool success) {
    // If the sender has sufficient funds to send
    // and the amount is not zero, then send to
    // the given address
    if (balances[msg.sender] >= _amount 
      && _amount > 0
      && balances[_to] + _amount > balances[_to]) {
      balances[msg.sender] -= _amount;
      balances[_to] += _amount;
      // Fire a transfer event for any
      // logic that's listening
      Transfer(msg.sender, _to, _amount);
        return true;
      } else {
        return false;
      }
   }
}