Equality in Object Oriented Languages

Traditional programming languages provide a simplified view of equality. Many programmers have apparently inferred that equality itself is a simple concept — a matter of writing ‘= ’ in the right place and leaving the rest to the compiler. Equality tests involve semantic relationships, how-ever, and it follows that a compiler cannot generate correct equality tests for user-defined types. In the sophisticated programming environments provided by modern object oriented languages, programmers must have a thorough understanding of equality if they are to implement it correctly and efficiently.