Which symbol is used to begin a line comment in C?

Concept

Comments are explanatory text that the C implementation removes during translation, so they do not become executable program statements.

C provides line-comment syntax for text that continues to the next newline and block-comment syntax for text enclosed by paired delimiters.

Application

The token // starts a line comment. Every character after // on that source line is part of the comment until the next newline.

Contrast

• The pair /* ... */ delimits a block comment and uses both an opening and a closing marker.

• The symbol # introduces preprocessing directives such as #include.

• The token -- is the decrement operator in C.

Result

Therefore, the symbol used to begin a line comment in C is //.