Question

Which of the following is not a correct C++ comment ?

• A. /*comment*/
• B. /*comment*\\
• C. //'comment*/
• D. /*//comment/*/

Answer 1

Answer:

B. /*comment*\\

C++ Comment Syntax Overview

• Single-line comments: Represented by //. Any text following this marker on the same line is ignored by the compiler.
• Multi-line (Block) comments: Represented by /* ... */. Everything placed between these delimiters is treated as a comment, allowing for documentation that spans multiple lines or portions of a line.

Key Rules and Constraints

1. Nested Comments: C++ does not support nested block comments. Attempting to wrap a block comment within another (e.g., /* /* ... */ */) will result in a compilation error because the compiler interprets the first */ as the end of the entire comment block.
2. Invalid Syntax: Using syntax markers incorrectly, such as mixing styles or omitting delimiters, leads to syntax errors. For example, using // to start a multi-line block without repeating the marker on each line or attempting to use invalid characters within the comment markers is prohibited.
3. Compiler Behavior: Comments are treated as white space by the C++ preprocessor and are completely removed before the compilation process begins.
4. Best Practices: While // is widely used for brief descriptions, /* */ is often preferred for temporarily commenting out large segments of code during debugging.