Debugging in C++ : <p>I came across this code snippet. Can you explain how to use this debugging in the program.</p>

<pre><code>#ifdef TESTING 
#define DEBUG fprintf(stderr, "====TESTING====\n") 
#define VALUE(x) cerr &lt;&lt; "The value of " &lt;&lt; #x &lt;&lt; " is " &lt;&lt; x &lt;&lt; endl 
#define debug(...) fprintf(stderr, __VA_ARGS__) 
#else 
#define DEBUG 
#define VALUE(x) 
#define debug(...) 
#endif 
</code></pre>
