3
I think that the classic
https://solidity.readthedocs.io/en/v0.5.13/abi-spec.html#types
is a good choice to begin.
Your error is simply the result of a tentative sum of type address with type string: it cannot work. In a previous version of the compiler it could have worked for conventional reasons: in that case the + operator in the kecca256 parentheses ...
2
You're missing the fact that "left" doesn't indicate "bigger", just semantics.
It's not as if values in memory appear left or right to each other.
Consider the following 32-bit integer 0x00112233:
It's little-endian representation is "0x33 at the lowest address ... 0x00 at the highest address"
It's big-endian representation is "0x00 at the lowest address ....
2
What is the meaning of stipend if transactions are always have gas limit set by sender?
Not really. When EOA calls contract A, the gas limit is set in the transaction, this is true. However, when contract A calls contract B, contract A may set limit on how much gas the contract B is allowed to spend. This limit may be lower than the remaining gas ...
2
Remix IDE is not authoritative. If it crashes, it's a failure of the simulation. In the end, the network block gasLimit is a hard stop. That value is voted on by miners and has been known to drop during periods of high congestion. Caution about cutting it too close.
I think you should have a look over here. https://blog.b9lab.com/getting-loopy-with-...
1
You are doing the invocation wrong, try with the following:
it("should keep the contract owner", async () => {
let instance = await Example.deployed();
let address = await instance.getContractOwner.call({from: accounts[0]});
// console.log(address);
assert.equal(address.valueOf(), "0x67F4CfB03aA5E2E71De1470ae26adB7e33B7892E", "the address is ...
1
The problem is that you try to assign the result of the keccak256 operation, which is of type 'bytes32', to the variable 'examsFinalHash', which is of type 'string storage ref'. Wherever your declare 'examsFinalHash', it must be of type bytes32 to store the result. bytes32 examsFinalHash;
1
The short answer is No.
What you are trying to do doesn't map to how this platform works. Normal assumptions about temporal time don't apply. Normal intuitions about execution time don't apply.
The blockTime is the only, admittedly tenuous, connection to temporal time available.
I'll break that down a little more.
Nodes process all transactions, but ...
1
This looks like two or more questions, to me.
A high-level question is the overall data layout. I'm not convinced this layout is ideal. It is usually best to think about readability and simplicity first and optimize later. With that in mind, I would probably tackle it with this: https://github.com/rob-Hitchens/UnorderedKeySet/blob/master/contracts/...
1
Try this declaration for person:
Person memory govt = Person(owner, 'Owner', 'Owner', 0, 'None', new uint[](0), new uint[](0));
I'd recommend reading a little more about arrays in Solidity. You'll need to decide if you want your arrays to be memory or storage, which is very dependent on what your goals are. Since you've assigned them to size zero, please ...
1
The stipend is 2300, not 23000.
A scenario where this stipend is not enough:
Changing a state-variable from zero to non-zero.
1
You are using solidity v0.4 I'd suggest to use v0.5 instead
In solidity v0.4 the following generates a warning because x and y are not initialized.
function teste() public returns (int[] v) {
int[] x;
int[] y;
}
They don't have memory modifier so they refer to storage. They are not assigned a slot so by default they refer to slot 0 on storage ...
1
If you refer to the docs about globally available variables, the two variables that will be useful in this case are
gasleft() returns (uint256)
and
tx.gasprice (uint)
The former will return the amount of gas that is remaining, and the latter gives you the gas price set for this transaction.
With that, the amount of gas to burn is
gasToBurn = ...
1
According to the official documentation:
NatSpec currently does NOT apply to public state variables (see solidity#3418), even if they are declared public and therefore do affect the ABI.
1
As of version 0.5.12, Solidity includes an assembly function chainid() that provides access to the new CHAINID opcode:
function getChainID() external view returns (uint256) {
uint256 id;
assembly {
id := chainid()
}
return id;
}
To use it, ensure you set the compiler's EVM version to Istanbul with the --evm-version istanbul flag.
...
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