Echo statement in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the echo statement do in PHP?

The echo statement outputs one or more strings to the web page or console. It is used to display text or variables.

beginner

How do you output the text Hello, World! using echo in PHP?

Use echo "Hello, World!"; to print the text on the screen.

intermediate

Can echo output multiple strings separated by commas? Give an example.

Yes, echo can output multiple strings separated by commas. Example: echo "Hello", " ", "World!"; outputs Hello World!.

intermediate

Is echo a function or a language construct in PHP?

echo is a language construct, not a function. This means you can use it without parentheses.

beginner

What happens if you forget the semicolon ; after an echo statement?

PHP will show a syntax error because semicolons mark the end of statements. Always end echo with a semicolon.

Which of the following is the correct way to output text using echo in PHP?

A print("Hello World!")

B echo "Hello World!";

C echo(Hello World!);

D print Hello World!;

echo "Hello World!"; is correct syntax. Option A uses print but misses semicolon. Option C has missing quotes. Option D is invalid syntax.

What will this code output?
echo "PHP", " is fun!";

A PHP is fun!

B PHP,is fun!

C PHP is fun!;

D Error

Using commas in echo outputs the strings one after another without extra characters.

Is it necessary to use parentheses with echo?

A Yes, always

B No, never

C Optional, but usually not used

D Only when outputting variables

echo is a language construct, so parentheses are optional but usually omitted.

What type of error occurs if you forget the semicolon after echo?

A Syntax error

B Runtime error

C Logical error

D No error

Forgetting the semicolon causes a syntax error because PHP expects statements to end with semicolons.

Which of these is NOT a valid way to use echo?

A echo "Hello";

B echo("Hello");

C echo "Hello", " World!";

D echo Hello;

Option D is invalid because strings must be in quotes.

Explain how the echo statement works in PHP and how to use it to display text.

Think about how you tell PHP to show words on the screen.

Describe the difference between using commas and concatenation with echo to output multiple strings.

Consider how you join words together or list them separately.

Practice

1. What does the echo statement do in PHP?

easy

A. It stores data in a variable.

B. It creates a function.

C. It prints text or variables to the screen.

D. It deletes a file.

Solution

1. Step 1: Understand the purpose of echo

   The echo statement is used to output text or variables to the screen in PHP.

2. Step 2: Compare with other options

   Other options describe different PHP actions like storing data, creating functions, or deleting files, which are not done by echo.

3. Final Answer:

   It prints text or variables to the screen. -> Option C

4. Quick Check:

   Echo = print output [OK]

Hint: Echo always shows output on the screen [OK]

Common Mistakes:

• Thinking echo stores data
• Confusing echo with function creation
• Assuming echo deletes files

2. Which of the following is the correct syntax to print the text Hello World using echo in PHP?

easy

A. echo "Hello World";

B. echo (Hello World);

C. echo 'Hello World';

D. echo Hello World;

Solution

1. Step 1: Check the syntax for echo with text

   Text must be inside quotes (single or double) when printed with echo. echo "Hello World"; uses double quotes and ends with a semicolon.

2. Step 2: Identify syntax errors in other options

   echo Hello World; misses quotes around text. echo 'Hello World' misses semicolon. echo (Hello World); incorrectly uses parentheses without quotes.

3. Final Answer:

   echo "Hello World"; -> Option A

4. Quick Check:

   Text in quotes + semicolon = correct echo syntax [OK]

Hint: Always put text inside quotes and end with semicolon [OK]

Common Mistakes:

• Forgetting quotes around text
• Missing semicolon at end
• Using parentheses incorrectly

3. What will be the output of the following PHP code?

<?php
$name = "Alice";
echo "Hello, $name!";
?>

medium

A. Hello, $name!

B. Hello, Alice!

C. Hello, !

D. Syntax Error

Solution

1. Step 1: Understand variable interpolation in double quotes

   In PHP, variables inside double quotes are replaced by their values. Here, $name is "Alice".

2. Step 2: Determine the output of echo

   The echo statement prints "Hello, Alice!" because $name is replaced by "Alice".

3. Final Answer:

   Hello, Alice! -> Option B

4. Quick Check:

   Variables in double quotes show values [OK]

Hint: Variables inside double quotes print their values [OK]

Common Mistakes:

• Expecting variable name printed literally
• Using single quotes which don't interpolate
• Assuming syntax error due to variable

4. Identify the error in the following PHP code:

<?php
echo 'Welcome to PHP!";
?>

medium

A. Incorrect use of echo keyword

B. Missing semicolon at the end

C. Variable not defined

D. Mismatched quotes in echo statement

Solution

1. Step 1: Check the quotes used in echo

   The echo statement starts with a single quote but ends with a double quote, causing mismatched quotes.

2. Step 2: Understand PHP string syntax

   Strings must start and end with the same type of quote (both single or both double). Mismatched quotes cause syntax errors.

3. Final Answer:

   Mismatched quotes in echo statement -> Option D

4. Quick Check:

   Quotes must match in strings [OK]

Hint: Start and end quotes must be the same type [OK]

Common Mistakes:

• Mixing single and double quotes
• Forgetting semicolon
• Assuming variable error instead

5. You want to print the following sentence exactly as it is, including the dollar sign:
The price's $price.
Which echo statement will produce this output correctly?

hard

A. echo "The price's \$price.";

B. echo 'The price's $price.';

C. echo "The price's $price.";

D. echo 'The price's \$price.';

Solution

1. Step 1: Understand variable interpolation and escaping

   In double quotes, $ starts variable interpolation. To print a literal $, it must be escaped with a backslash (\$).

2. Step 2: Analyze each option

   echo "The price's $price."; prints "The price's " followed by $price (undefined, empty), resulting in "The price's .". echo 'The price's $price.'; syntax error due to unescaped apostrophe in "price's". echo "The price's \$price."; escapes $ correctly in double quotes (apostrophe fine), printing exactly. echo 'The price's \$price.'; syntax error from unescaped apostrophe (backslash literal if fixed).

3. Final Answer:

   echo "The price's \$price."; -> Option A

4. Quick Check:

   Escape $ in double quotes with \$ [OK]

Hint: Escape $ with \$ inside double quotes to print it [OK]

Common Mistakes:

• Not escaping $ in double quotes
• Using backslash in single quotes incorrectly
• Syntax error with unescaped apostrophe in single quotes