/in/foo.cc: In function 'void cp(int, int)':
/in/foo.cc:49:9: error: 'len' was not declared in this scope
   tmp[++len]=dot[i];
         ^~~
/in/foo.cc:51:17: error: 'len' was not declared in this scope
  sort(tmp+1,tmp+len+1,cmp2);
                 ^~~