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PHP: Time

Have you ever wondered how time is stored in a computer? Turning the computer on and off has no effect on the clock. We can there conclude that the clock in the computer works by itself.

This is very much the case. The computer's main clock is a hardware clock, it lives its own life and has its own battery. When you turn on the computer, it reads the data from this clock, writes it to its memory and starts counting the time itself. This clock is called a system clock. Any change in the system clock will also affect the hardware clock.

In most operating systems (Linux, Unix, MacOS) the system time is presented in Unix time format. It's defined as the number of seconds elapsed since midnight (00:00:00 UTC) on January 1, 1970 (Thursday). The time since then is called the "Unix Epoch". Unix time is represented by an integer number which is incremented with each passing second without needing calculations to determine the year, month, day, hour or minute, which is easy for people to understand.

A specific date in Unix time format is called a timestamp. For example, PHP uses the time() function to get the current timestamp.


time(); // 1532435204


Complete the implementation of the getYear() function, which returns the year of the timestamp passed:

Call examples:


getYear(1532435204); // 2018
  • To round down, use the floor()
  • Don't forget to convert the resulting number to the int type
The exercise doesn't pass checking. What to do? 😶

If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:

  • Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨

Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.

My code is different from the teacher's one 🤔

It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.

In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.

I've read the lessons but nothing is clear 🙄

It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.

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