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What is the output of the following PHP code: function greet($name) { echo "Hello, " . $name . "!"; } greet("John");
What is the output of the following PHP code: function greet($name) { echo "Hello, " . $name . "!"; } greet("John");
What is the output of the following PHP code: function add($a, $b) { return $a + $b; } echo add(5, 3);
What is the output of the following PHP code: function add($a, $b) { return $a + $b; } echo add(5, 3);
What is the output of the following PHP code: function is_even($num) { if ($num % 2 == 0) { return true; } else { return false; } } echo is_even(10) ? 'even' : 'odd';
What is the output of the following PHP code: function is_even($num) { if ($num % 2 == 0) { return true; } else { return false; } } echo is_even(10) ? 'even' : 'odd';
What is the output of the following PHP code: function get_max($a, $b) { if ($a > $b) { return $a; } else { return $b; } } echo get_max(5, 3);
What is the output of the following PHP code: function get_max($a, $b) { if ($a > $b) { return $a; } else { return $b; } } echo get_max(5, 3);
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What is the output of the following PHP code: function greet_all($names) { foreach ($names as $name) { echo "Hello, " . $name . "!"; } } $names = array('John', 'Jane', 'Bob'); greet_all($names);
What is the output of the following PHP code: function greet_all($names) { foreach ($names as $name) { echo "Hello, " . $name . "!"; } } $names = array('John', 'Jane', 'Bob'); greet_all($names);
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What is the output of the following PHP code: `function swap(&$a, &$b) { $temp = $a; $a = $b; $b = $temp; } $x = 5; $y = 10; swap($x, $y); echo $x . ', ' . $y;
What is the output of the following PHP code: `function swap(&$a, &$b) { $temp = $a; $a = $b; $b = $temp; } $x = 5; $y = 10; swap($x, $y); echo $x . ', ' . $y;
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What is the output of the following PHP code: `function increment(&$value) { $value++; } $counter = 5; increment($counter); echo $counter;
What is the output of the following PHP code: `function increment(&$value) { $value++; } $counter = 5; increment($counter); echo $counter;
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What is the output of the following PHP code: `function double(&$value) { $value *= 2; } $number = 5; double($number); echo $number;
What is the output of the following PHP code: `function double(&$value) { $value *= 2; } $number = 5; double($number); echo $number;
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What is the output of the following PHP code: `function append(&$string, $append) { $string .= $append; } $str = 'Hello'; append($str, ', World'); echo $str;
What is the output of the following PHP code: `function append(&$string, $append) { $string .= $append; } $str = 'Hello'; append($str, ', World'); echo $str;
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What will be the value of $num after running the following PHP code?
function modify(&$num) { $num += 100; } $num = 50; modify($num); echo $num;
What will be the value of $num after running the following PHP code?
function modify(&$num) { $num += 100; } $num = 50; modify($num); echo $num;
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What is the final output of the following PHP code?
function reverseString(&$str) { $str = strrev($str); } $original = 'hello'; reverseString($original); echo $original;
What is the final output of the following PHP code?
function reverseString(&$str) { $str = strrev($str); } $original = 'hello'; reverseString($original); echo $original;
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What will be the output of the following PHP code?
function multiplyByTen(&$value) { $value *= 10; } $number = 4; multiplyByTen($number); echo $number;
What will be the output of the following PHP code?
function multiplyByTen(&$value) { $value *= 10; } $number = 4; multiplyByTen($number); echo $number;
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After executing the following PHP code, what will be the value of $a?
function exchange(&$x, &$y) { $temp = $x; $x = $y; $y = $temp; } $a = 1; $b = 2; exchange($a, $b); echo $a;
After executing the following PHP code, what will be the value of $a?
function exchange(&$x, &$y) { $temp = $x; $x = $y; $y = $temp; } $a = 1; $b = 2; exchange($a, $b); echo $a;
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What will be the final value of $text after the following PHP code is executed?
function addSuffix(&$string, $suffix) { $string .= $suffix; } $text = 'good'; addSuffix($text, 'bye'); echo $text;
What will be the final value of $text after the following PHP code is executed?
function addSuffix(&$string, $suffix) { $string .= $suffix; } $text = 'good'; addSuffix($text, 'bye'); echo $text;
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Study Notes
PHP User Defined Functions
- A user-defined function in PHP is a block of code that can be executed multiple times from different parts of a script.
- To create a user-defined function, the
functionkeyword is used, followed by the name of the function and parentheses that contain the function's arguments. - User-defined functions can accept arguments, which are values passed to the function when it's called.
- Functions can also return values using the
returnstatement. - Functions can be reused throughout a script, making it easier to maintain and update code.
Creating a User-Defined Function
- A user-defined function is defined using the
functionkeyword, followed by the function name and parentheses that contain the function's arguments. - The function body is enclosed in curly braces
{}and contains the code that's executed when the function is called. - Example:
function greet($name) { echo "Hello, $name!"; }
Calling a User-Defined Function
- A user-defined function is called by writing the function name followed by parentheses that contain the function's arguments.
- Example:
greet('John'); - When a function is called, the code inside the function body is executed, and any values returned by the function are returned to the caller.
Function Arguments and Return Values
- Functions can accept arguments, which are values passed to the function when it's called.
- Arguments are specified in the function definition and are separated by commas.
- Example:
function add($a, $b) { return $a + $b; } - Functions can also return values using the
returnstatement. - Example:
function getHello() { return "Hello, World!"; }
Best Practices for User-Defined Functions
- Use meaningful and descriptive names for your functions.
- Keep your functions concise and focused on a single task.
- Use functions to organize and reuse code throughout your script.
- Document your functions with comments to explain what they do and how they work.
PHP User-Defined Functions with Arguments by Reference
- In PHP, functions can take arguments by reference using the
&symbol before the parameter name in the function definition. - When passing arguments by reference, changes made to the argument within the function affect the original variable outside the function.
- By default, PHP functions pass arguments by value, meaning a copy of the original value is passed and changes within the function do not affect the original variable.
Examples and Output
- Example code:
function add(&$num) { $num++; } $a = 5; add($a); echo $a;Output:6 - In this example, the function
addtakes an argument by reference, increments it, and the change is reflected in the original variable$aoutside the function.
Key Points
- Passing arguments by reference allows functions to modify external variables.
- The
&symbol is used to indicate pass-by-reference in function definitions. - Without the
&symbol, arguments are passed by value, and changes within the function do not affect the original variable.
PHP User-Defined Functions with Arguments by Reference
- In PHP, functions can take arguments by reference using the
&symbol before the parameter name in the function definition. - When passing arguments by reference, changes made to the argument within the function affect the original variable outside the function.
- By default, PHP functions pass arguments by value, meaning a copy of the original value is passed and changes within the function do not affect the original variable.
Examples and Output
- Example code:
function add(&$num) { $num++; } $a = 5; add($a); echo $a;Output:6 - In this example, the function
addtakes an argument by reference, increments it, and the change is reflected in the original variable$aoutside the function.
Key Points
- Passing arguments by reference allows functions to modify external variables.
- The
&symbol is used to indicate pass-by-reference in function definitions. - Without the
&symbol, arguments are passed by value, and changes within the function do not affect the original variable.
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Description
Test your knowledge of user-defined functions in PHP, including how to create and use them in a script. Covers function arguments, return values, and more.
