Blockchain By Example

Time in Solidity

As you will notice, in the constructor, we used the keyword now to set the auction start time, whereas the auction's end is calculated by adding to the auction start time a number of hours defined by the _biddingTime argument.

The now keyword is an integer variable that returns the block's timestamp (it's an alias for the special global variable block.timestamp), in which the contract was embedded. Solidity also provides us with some helpful time units (seconds, minutes, hours, days, weeks, and years) that can be applied to a variable as a suffix, to automatically convert a unit to the equivalent time, in seconds. In your constructor, the elapsed number of hours (_biddingTime * 1 hours) is automatically converted to seconds ...