How can missing curly braces in PHP functions or if statements lead to errors like unexpected $end?

Missing curly braces in PHP functions or if statements can lead to errors like "unexpected $end" because the code interpreter expects to find a closing brace to match the opening brace. Without the proper braces, the interpreter may reach the end of the file or block of code unexpectedly, resulting in a syntax error. To solve this issue, always ensure that opening and closing curly braces are properly used to define the beginning and end of code blocks.

// Incorrect code without curly braces
function myFunction() 
    echo "Hello World";

// Correct code with curly braces
function myFunction() {
    echo "Hello World";
}