In PHP, what is the key difference between the echo and print constructs when outputting text?

Introduction / Context:
PHP provides two commonly used language constructs for sending output to the browser: echo and print. They look similar and, in most cases, can be used interchangeably to display text or variables. However, there are subtle differences between them, particularly regarding return values and argument handling. Understanding these differences helps you answer interview questions precisely and choose the most appropriate construct in different coding situations.

Given Data / Assumptions:

• We are using echo and print in typical PHP scripts to output text and variables.
• Both are language constructs rather than regular functions, so parentheses are optional in many cases.
• We want to know the behavioural differences that matter in practice.
• Performance differences are minor and not the main focus of this conceptual question.

Concept / Approach:
echo and print both send output to the standard output stream, typically the browser. echo can take one or more comma separated arguments, although passing a single concatenated string is more common. It does not return a value. print, on the other hand, behaves like a function that accepts exactly one argument and returns 1, which means it can be used in expressions or conditions. These characteristics lead to slight differences in how you can use each construct syntactically, even though in everyday usage they appear very similar.

Step-by-Step Solution:
Step 1: Recognize that echo is a language construct used simply as echo "Hello"; to output text. Step 2: Understand that echo can be called with multiple parameters such as echo "Hello ", $name; which outputs concatenated content without requiring a single combined string. Step 3: Note that echo does not return a value, so you cannot meaningfully assign its result to a variable or use it in expressions. Step 4: Learn that print also outputs text but takes only one argument, so print "Hello" is valid, whereas print "Hello", "World" is not. Step 5: Remember that print returns 1, allowing it to be used in expressions like $x = print "Hello"; which first outputs "Hello" and then assigns 1 to $x.

Verification / Alternative check:
You can test these behaviours easily. A statement like echo "A", "B"; produces "AB" without errors, demonstrating multiple arguments. However, print "A", "B"; causes a parse error because print expects only one argument. Trying $result = echo "A"; will also fail because echo does not return a value, while $result = print "A"; will correctly assign 1 to $result after printing the text. These experiments confirm the conceptual differences.

Why Other Options Are Wrong:
Option B incorrectly states that echo is only for debugging and print is only for file logging; in reality, both are used for regular page output. Option C is wrong because neither echo nor print automatically escapes or strips HTML; they output exactly what they are given, and escaping must be handled by functions like htmlspecialchars(). Option D is incorrect because echo and print are not database or file upload functions at all; they are output constructs.

Common Pitfalls:
Developers sometimes overemphasize performance differences between echo and print, which are negligible in most applications. Another pitfall is misunderstanding return values and trying to use echo in contexts where a return value is expected. In practice, echo is commonly preferred for simple output due to its flexibility with multiple arguments and slightly less verbosity, while print is occasionally used when a return value is desired or for stylistic reasons.

Final Answer:
Both echo and print output text, but echo can take multiple arguments and does not return a value, while print takes a single argument and returns 1, which allows it to be used in expressions.