Chapter 7 - Practical PHP

Question 1

What is printf conversion specifier would you use to display a floating point number?

Answer 1

The conversion specifier you would use to display a floating-point number is %f.

Question 2

What printf statement could be used to take the input string “Happy Birthday” and output the string “**Happy”?

Answer 2

To take the input string “Happy Birthday” and output the string “**Happy”, you could use a printf statement such as: printf(“%’*7.5s”, “Happy Birthday”);

Question 3

To send the output from printf to a variable instead of to a browser, what alternative function would you use?

Answer 3

To send the output from printf to a variable instead of to a browser, you would use sprintf instead.

Question 4

How would you create a Unix timestamp for 7:11 am. on May 2, 2016?

Answer 4

To create a Unix timestamp for 7:11am on May 2nd 2016, you could use the command: $timestamp = mktime(7, 11, 0, 5, 2, 2016);

Question 5

Which file access mode would you use with fopen to open a file in write and read mode, with the file truncated and the file pointer at the start?

Answer 5

You would use the “w+” file access mode with fopen to open a file in write and read mode, with the file truncated and the file pointer at the start.

Question 6

What is the PHP command for deleting the file file.txt?

Answer 6

The PHP command for deleting the file file.txt is: unlink(‘file.txt’);

Question 7

Which HP function is used to read in an entire file in one go, even from across the web?

Answer 7

The PHP function file_get_contents is used to read in an entire file in one go. It will also read them from across the Internet if provided with a URL.

Question 8

Which PHP superglobal variable holds the details on uploaded files?

Answer 8

The PHP superglobal associative array $_FILES contains the details about uploaded files.

Question 9

Which PHP function enables the running of system commands?

Answer 9

The PHP exec function enables the running of system commands.

Question 10

Which of the following tag styles is preferred in HTML5? <hr> or <hr>?

Answer 10

In HTML5 you can use either the XHTML style of tag (such as <hr>) or the standard HTML4 style (such as <hr>). It’s entirely up to you or your company’s coding style.