How to find out if an Ethereum address is a contract?
Yes you can, by using some EVM assembly code to get the address’ code size: function isContract(address addr) returns (bool) { uint size; assembly { size := extcodesize(addr) } return size > 0; }
ethereum
Are there null like thing in solidity
In solidity every variable is set to 0 by default. You should think of mappings as all possible combinations are set to 0 by default. In your specific case I would use the following: if (buyers[msg.sender].amount == 0)
How do I get the balance of an account in Ethereum?
On the Web: (Not programmatic, but for completeness…) If you just want to get the balance of an account or contract, you can visit http://etherchain.org or http://etherscan.io. From the geth, eth, pyeth consoles: Using the Javascript API, (which is what the geth, eth and pyeth consoles use), you can get the balance of an account … Read more
What is address(0) in Solidity
Within an Ethereum transaction, the zero-account is just a special case used to indicate that a new contract is being deployed. It is literally ‘0x0’ set to the to field in the raw transaction. Every Ethereum transaction, whether it’s a transfer between two external accounts, a request to execute contract code, or a request to … Read more