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@@ -125,24 +125,6 @@ Example::
}
}
-Are timestamps (``now,`` ``block.timestamp``) reliable?
-=======================================================
-
-This depends on what you mean by "reliable".
-In general, they are supplied by miners and are therefore vulnerable.
-
-Unless someone really messes up the blockchain or the clock on
-your computer, you can make the following assumptions:
-
-You publish a transaction at a time X, this transaction contains same
-code that calls ``now`` and is included in a block whose timestamp is Y
-and this block is included into the canonical chain (published) at a time Z.
-
-The value of ``now`` will be identical to Y and X <= Y <= Z.
-
-Never use ``now`` or ``block.hash`` as a source of randomness, unless you know
-what you are doing!
-
Can a contract function return a ``struct``?
============================================
@@ -155,37 +137,6 @@ Enums are not supported by the ABI, they are just supported by Solidity.
You have to do the mapping yourself for now, we might provide some help
later.
-What is the deal with ``function () { ... }`` inside Solidity contracts? How can a function not have a name?
-============================================================================================================
-
-This function is called "fallback function" and it
-is called when someone just sent Ether to the contract without
-providing any data or if someone messed up the types so that they tried to
-call a function that does not exist.
-
-The default behaviour (if no fallback function is explicitly given) in
-these situations is to throw an exception.
-
-If the contract is meant to receive Ether with simple transfers, you
-should implement the fallback function as
-
-``function() payable { }``
-
-Another use of the fallback function is to e.g. register that your
-contract received ether by using an event.
-
-*Attention*: If you implement the fallback function take care that it uses as
-little gas as possible, because ``send()`` will only supply a limited amount.
-
-Is it possible to pass arguments to the fallback function?
-==========================================================
-
-The fallback function cannot take parameters.
-
-Under special circumstances, you can send data. If you take care
-that none of the other functions is invoked, you can access the data
-by ``msg.data``.
-
Can state variables be initialized in-line?
===========================================
@@ -230,13 +181,6 @@ Better use ``for (uint i = 0; i < a.length...``
See `struct_and_for_loop_tester.sol <https://github.com/fivedogit/solidity-baby-steps/blob/master/contracts/65_struct_and_for_loop_tester.sol>`_.
-What character set does Solidity use?
-=====================================
-
-Solidity is character set agnostic concerning strings in the source code, although
-UTF-8 is recommended. Identifiers (variables, functions, ...) can only use
-ASCII.
-
What are some examples of basic string manipulation (``substring``, ``indexOf``, ``charAt``, etc)?
==================================================================================================
@@ -441,23 +385,6 @@ The correct way to do this is the following::
}
}
-What is the difference between ``bytes`` and ``byte[]``?
-========================================================
-
-``bytes`` is usually more efficient: When used as arguments to functions (i.e. in
-CALLDATA) or in memory, every single element of a ``byte[]`` is padded to 32
-bytes which wastes 31 bytes per element.
-
-Is it possible to send a value while calling an overloaded function?
-====================================================================
-
-It's a known missing feature. https://www.pivotaltracker.com/story/show/92020468
-as part of https://www.pivotaltracker.com/n/projects/1189488
-
-Best solution currently see is to introduce a special case for gas and value and
-just re-check whether they are present at the point of overload resolution.
-
-
******************
Advanced Questions
******************
@@ -503,23 +430,6 @@ Note2: Optimizing storage access can pull the gas costs down considerably, becau
currently do not work across loops and also have a problem with bounds checking.
You might get much better results in the future, though.
-What does ``p.recipient.call.value(p.amount)(p.data)`` do?
-==========================================================
-
-Every external function call in Solidity can be modified in two ways:
-
-1. You can add Ether together with the call
-2. You can limit the amount of gas available to the call
-
-This is done by "calling a function on the function":
-
-``f.gas(2).value(20)()`` calls the modified function ``f`` and thereby sending 20
-Wei and limiting the gas to 2 (so this function call will most likely go out of
-gas and return your 20 Wei).
-
-In the above example, the low-level function ``call`` is used to invoke another
-contract with ``p.data`` as payload and ``p.amount`` Wei is sent with that call.
-
What happens to a ``struct``'s mapping when copying over a ``struct``?
======================================================================