/in/lab4.c: In function 'strfind2':
/in/lab4.c:15:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < strlen(arr); i++)
                       ^
/in/lab4.c: In function 'main':
/in/lab4.c:256:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for (int zzwi = 0; zzwi < strlen(zzw); zzwi++) //judge whether it is a variable
                                         ^