/in/foo.cc: In function 'int main()':
/in/foo.cc:30:9: warning: statement has no effect [-Wunused-value]
     b[j]==true;
     ~~~~^~~~~~
/in/foo.cc:25:7: warning: variable 'begin' set but not used [-Wunused-but-set-variable]
   int begin,longth;
       ^~~~~
/in/foo.cc:61:10: warning: 'longth' may be used uninitialized in this function [-Wmaybe-uninitialized]
     else if(longth==maxva)
          ^~