Block and Transaction Properties

• blockhash(uint blockNumber) returns (bytes32): hash of the given block - only works for 256 most recent, excluding current, blocks
• block.chainid (uint): current chain id
• block.coinbase (address payable): current block miner’s address
• block.difficulty (uint): current block difficulty
• block.gaslimit (uint): current block gaslimit
• block.number (uint): current block number
• block.timestamp (uint): current block timestamp as seconds since unix epoch
• gasleft() returns (uint256): remaining gas
• msg.data (bytes calldata): complete calldata
• msg.sender (address payable): sender of the message (current call)
• msg.sig (bytes4): first four bytes of the calldata (i.e. function identifier)
• msg.value (uint): number of wei sent with the message
• tx.gasprice (uint): gas price of the transaction
• tx.origin (address payable): sender of the transaction (full call chain)

Now let's learn how to use them

See the data types they have written inside the brackets near pre-defined functions are the datatypes that is returned when get called; not to confused with Arguments

Here are some examples how to use them

pragma solidity ^0.8.3;
contract Task2{
    // create a function to return gas price of transaction and sender of transaction
  
    //tx.gasprice (uint)
     function getGasPrice()public view returns (uint){
          return tx.gasprice  ;
    }
    
    //tx.origin (address payable)
    function getTransactionSender()public view returns (address){
          return tx.origin  ;
    }


}

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