Cracking PHP Interviews : 80+ Question and Answers

Discover PHP, a general language called hypertext processor for dynamic web applications; it supports procedural and object oriented programming with PHP tags that print hello world in a browser.

Explore how PHP handles function name case sensitivity with practical examples showing that function names are case sensitive and calls with different case fail to execute.

Explore the contrast between strongly typed languages like Java and PHP's loosely typed, dynamically determined types, and see how PHP infers types at runtime.

learn how to set up a PHP development environment by downloading and installing the necessary software on Windows, Linux, or macOS, and configure it with popular cross-platform options.

Discover how Composer simplifies PHP dependency management by downloading, updating, and autoloading libraries like Guzzle and Monologue, ensuring secure, updated components for your application.

Discover Packagist as the repository for PHP packages, where Composer downloads dependencies, developers publish packages, and others browse and install these libraries from the site.

Learn how to execute a PHP script from the command line, using the command prompt to run PHP code directly from the terminal.

Explore how virtual hosts enable hosting multiple websites on one server, using ip-based addressing or name-based addressing to run several domains on a single machine.

XAMPP and WAMP bundles provide preconfigured Apache, MySQL, and PHP for easy development, avoiding manual setup. Compare their integrated environments as flexible options for PHP projects.

Explore the Apache web server, the most widely used web server, and how it handles client requests and PHP interpretation. Learn to configure Apache on Windows and Linux.

Learn to check the current php version and gather other system information by using the command line, with sample output showing versions such as 7.1.6.

Learn how an interpreter executes programs line by line, reading each instruction, handling blank lines, and printing outcomes as functions run.

The lecture shows that PHP is both compiled and interpreted, using a compiler to produce bytecode and an interpreter to execute it, with symbol tables for variables and constants.

Explore what a framework is as a collection of libraries built to achieve a specific goal, with Laravel as an example for building applications featuring routing, middleware, and CSRF protections.

mvc stands for model view controller, an application design pattern where the controller handles requests, the model supplies data, and the view presents the response.

Explore how data types provide storage for values, enable compiler optimizations, and dictate which operations are allowed, such as numeric multiplication for numbers.

Identify PHP data types, including integer, alphanumeric text (string), double, boolean, object, null, and resource, with examples like 1995 and 7.9, and true or false.

Explore the rules for declaring variables in PHP: variable names can start with underscores, may include numbers, but must avoid plus, minus, modulo operators, and commas.

Define constants in PHP using define function, which takes two parameters: the constant name and its value, with an example showing how to declare and view it in the browser.

Learn how the PHP constant() function retrieves values defined with define, with an example like main size 50. Compare it to static access by name.

Compare PHP constants and variables: constants use define, have global scope and cannot be reassigned; variables use simple assignment and follow local scoping rules across files.

Explore variable scopes in PHP, comparing local scope inside functions with global scope accessible across files, and learn how local and global variables are declared and accessed.

Explore what a string is in PHP, a data type that holds text as a collection of characters, with examples like words and sentences, and learn how to declare strings.

Compare single-quoted strings and double-quoted strings in PHP, showing how variables interpolate in double quotes but not in single quotes, and how outputs differ in examples.

Learn how to convert a string into array elements using the explode function with a space delimiter, as shown through an example.

Learn to convert an array into a string in PHP using the implode function, with a practical example showing how values are joined and output in the browser.

Learn how to concatenate two or more strings in PHP using the string concatenation operator, with examples showing combining variables and literals to produce a final output.

Differentiate echo and print in PHP: echo has no return value, can be used in expressions, and accepts multiple parameters, while print uses a single parameter and is slower.

Explore how static variables persist across function calls using the static keyword, keeping local values after a function ends and enabling continuity between invocations.

Discover PHP magic constants like __LINE__ and __FILE__, which reveal line numbers and absolute file paths to aid debugging and logging when exceptions occur.

Discover how the trim() function in PHP removes leading and trailing whitespace from strings, demonstrated with a practical example. Keep string values clean by removing unwanted spaces.

Use a predefined PHP function to count the number of words in a string, demonstrated with a sample string.

Learn how a string reversing function in PHP takes any string and returns its reverse, with a simple hello world example.

Learn how to locate the position of a substring within a string using PHP's strpos function, including how the starting index is handled.

Discover how to change string cases in PHP using two predefined functions to convert strings to upper or lower case, with examples like converting 'Hello' to uppercase or lowercase.

Learn to replace a substring in PHP with the str_replace function. See how search, replace, and string parameters work in an example that changes 'bird' to 'Peter'.

Compare str_replace and str_ireplace in PHP, noting their case sensitivity differences and how each replaces substrings, along with variants that behave like the originals.

Explore the differences between printf() and print() in PHP and how each prints output. See how printf formats strings with placeholders to insert numbers.

Explore the differences between strstr and strchr, two C string functions that locate the first occurrence of a substring, and see why this topic features prominently in interviews.

Differentiate between strstr() and stristr(), explaining that the variant in the function name indicates case-insensitive behavior and how this affects string search results.

Discuss how to encode a string in PHP when passing data, using a built-in function to replace non-allowed characters with encoding, such as replacing spaces with %20.

Compare strings with strcmp and strncmp to distinguish full-string from prefix comparisons. Return zero when equal; strncmp compares up to n characters, such as six.

Discover how to strip html tags from data in PHP using the strip_tags function, with options to remove all tags or preserve specific tags through an allowed list.

Learn how the gettype() function in PHP returns the type of a variable, with examples for integers, booleans, strings, and objects.

Learn how heredoc and nowdoc let you define multi-line strings in php, with heredoc interpolating variables and nowdoc printing content literally.

Explore how the if-else statement evaluates an expression to true or false and decides which code runs, with true or false outcomes determining the statements inside the if block.

Demonstrate PHP switch statements as a flow control mechanism, compare with chained if conditions, and handle cases like daisy and lily using case blocks, break, and a default output.

Compare switch and if-else constructs by examining boolean expressions and multi-way branching. Use if for boolean or fixed-value checks, and switch for textual or numerical values, noting speed.

Explore the five PHP operator types: arithmetic, assignment, logical, unary, and comparison, with examples like +, -, *, /, %, ++, --, and ==, !=, >, <, >=, <=.

Explain the PHP identical operator and equals operator, noting that === checks type and value, while == checks only values, with examples like 1 === 1 and 1 == 1.

Explain pre and post increment and decrement operators in PHP. Learn how prefix increments before the variable and returns the updated value, while postfix returns the original value then increments.

Discover operator overloading, where a single operator can behave differently by operand types, such as plus for string concatenation or integer addition, with PHP 7.1 introducing it.

Explain how a while loop runs while the condition is true, using a counter x starting at 1 to print numbers 1 through 5 and stop when x becomes 6.

Explore the for loop in PHP, detailing its initialization, test, and increment expressions, and illustrate how a counter drives repeated execution with a practical number-printing example.

Explore the foreach loop in PHP as it iterates over arrays, retrieving values and keys. See the planets example, Mercury, Venus, and Mars, showing value-only and key-value outputs.

Explore how infinite loops arise in PHP across various loop types, see how a test condition fails to terminate, and learn strategies to prevent memory exhaustion and stack overflow.

Explore how to implement recursion in PHP by examining a factorial example, highlighting the base case and a function calling itself to compute the result.

Compare iteration and recursion to decide usage: use iteration for simple problems with memory limits and recursion for complex or unknown problems, noting recursion uses more memory.

Learn how the break statement terminates a loop in PHP, illustrated with a for loop that prints 1 through 4 and stops when the value exceeds 3.

See how the continue statement skips the rest of for loop body and goes to the next iteration, as the example prints 1, 2, 3, and 5 while skipping 4.

Learn how the PHP declare construct sets execution directives for a code block, its flow-control like syntax, and see a practical example of using declare.

Understand the differences between include and require in PHP, including how require stops script execution on failure while include only warns and continues.

Explore arrays in PHP, covering numeric indexed arrays, associative arrays with string keys, and multidimensional arrays, and how key-value pairs store and access data.

Master printing arrays in PHP and prep for interviews with practical questions and answers from Cracking PHP Interviews: 80+ questions and answers.

Understand the base address of an array and how memory stores and references its elements in PHP, as taught in the Cracking PHP Interviews course.

Explore key-value pairs in PHP arrays, including associative arrays with custom keys, accessing values by keys, and different ways to create key-value pairs in PHP 7.

Explore how the implode function turns array elements into a string and prints it in a browser, with the delimiter before or after the array, a common PHP interview topic.

Learn how to convert a string into an array in php with explode and convert an array into a string with implode, using spaces and dot delimiters in practical examples.

Learn to use array_merge to concatenate multiple arrays in PHP, enabling merging of input arrays and displaying the combined result.

Count the frequency of values in arrays with a values-counting function, illustrating how many people live in different cities. See how the return shows the frequency of each value.

Learn how to use the in_array function to check if a value exists in an array, returning true or false, with a practical Android example.

Use the array_push() function to append one or more elements to the end of an array in PHP, adding chemistry and biology to mathematics and physics.

Discover how array_chunk splits an array into equal-sized chunks for processing. The lecture uses a car brands example to show chunks of two elements each.

Learn how the extract() function creates a symbol table by assigning array values to variable names. See how keys map to variables and enable use of variable variables.

Understand functions as named blocks of code that perform tasks, using the function keyword. Start function names with a letter or underscore and allow letters, numbers, and underscores.

Explore the two main function types in PHP: user-defined and built-in, and learn how parameters and arguments shape function calls with practical examples.

Observe how call by value works by copying a variable into the function. Illustrate the copy in memory and the resulting output with a string example.

Demonstrate call by reference by passing a variable’s memory address to a function, allowing in-place modifications that reflect back in the original variable.