What are the common pitfalls when trying to display output using PHP's echo or print functions?

Common pitfalls when trying to display output using PHP's echo or print functions include forgetting to enclose strings in quotes, not properly concatenating strings and variables, and using incorrect syntax. To solve these issues, always enclose strings in quotes, use the concatenation operator (.) to combine strings and variables, and double-check the syntax for any errors.

// Incorrect way to display output
$name = "John";
echo Hello, $name;

// Correct way to display output
$name = "John";
echo "Hello, " . $name;