Comments. Two forms of comments are supported: single-line comments and delimited comments

Two forms of comments are supported: single-line comments and delimited comments. Single-line comments start with the characters // and extend to the end of the source line. Delimited comments start with the characters /* and end with the characters */. Delimited comments may span multiple lines.

comment:
single-line-comment
delimited-comment

single-line-comment:
// input-characters_opt

input-characters:
input-character
input-characters input-character

input-character:
Any Unicode character except a new-line-character

new-line-character:
Carriage return character (U+000D)
Line feed character (U+000A)
Next line character(U+0085)
Line separator character (U+2028)
Paragraph separator character (U+2029)

delimited-comment:
/* delimited-comment-text_opt asterisks /

delimited-comment-text:
delimited-comment-section
delimited-comment-text delimited-comment-section

delimited-comment-section:
/
asterisks_opt not-slash-or-asterisk

asterisks:
*
asterisks *

not-slash-or-asterisk:
Any Unicode character except / or *

Comments do not nest. The character sequences /* and */ have no special meaning within a // comment, and the character sequences // and /* have no special meaning within a delimited comment.

Comments are not processed within character and string literals.

The example

/* Hello, world program
This program writes “hello, world” to the console
*/
class Hello
{
static void Main() {
System.Console.WriteLine("hello, world");
}
}

includes a delimited comment.

The example

// Hello, world program
// This program writes “hello, world” to the console
//
class Hello // any name will do for this class
{
static void Main() { // this method must be named "Main"
System.Console.WriteLine("hello, world");
}
}

shows several single-line comments.