/in/foo.c: In function 'main':
/in/foo.c:6:19: warning: variable 'b' set but not used [-Wunused-but-set-variable]
  int k,i,fangda,n,b[1000];
                   ^
/in/foo.c:20:7: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(i-1>k)
      ~^~