What is a compile-time error?

A compile-time error is defined as an error that is detected during the compilation of the program. This type of error occurs when the code contains syntactical issues, such as incorrect use of language constructs, undeclared variables, or type mismatches, which prevent the compiler from producing an executable program. The compiler checks the source code for these errors before converting it into machine code.

Identifying errors at this stage is crucial because it allows developers to correct them early in the development process, ensuring that the code adheres to the programming language's syntax and rules. This early detection helps avoid runtime errors that can lead to program crashes or unexpected behavior when the program is executed.

In contrast, other options refer to errors detected at different stages or types of errors unrelated to syntax issues. For instance, errors during program execution or logical errors are identified after compilation and runtime, which do not align with the definition of compile-time errors.