Check out example codes for "how to comment in arduino". It will help you in understanding the concepts better.

Code Example 1

x = 5;  // This is a single line comment. Anything after the slashes is a comment           // to the end of the line  /* this is multiline comment - use it to comment out whole blocks of code  if (gwb == 0){   // single line comments are OK inside a multiline comment x = 3;           /* but not other multiline comments - this is invalid */ } // don't forget the "closing" comment - they have to be balanced! */

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