strcmp of .WAV file

Hii all,

I was referring one of the code and bit curious to understand. If suppose I have a wav file say(XYZ.wav)
As per my understanding mylen will have mylen =7-4; Want to know strcmp function?

So strcmp will be strcmp(XYZ.wav + 3,".wav") -> so how it would compare (.wav with .wav). Please find the code snippet below.

int mylen=strlen(;// compare last 4 characters
     if ((strcmp( + mylen,".WAV")==0) || (strcmp( + mylen,".wav")==0)) {