How can PHP developers use error reporting and display settings to identify and handle issues related to undefined variables in their code?

When PHP developers encounter issues related to undefined variables in their code, they can use error reporting and display settings to identify and handle these problems. By setting error reporting to E_ALL, developers can ensure that all errors, including those related to undefined variables, are displayed. They can also use isset() or empty() functions to check if a variable is defined before using it in their code.

// Set error reporting to display all errors
error_reporting(E_ALL);

// Check if a variable is defined before using it
if(isset($variable_name)){
    // Use the variable here
} else {
    // Handle the case where the variable is undefined
}