/in/foo.cc: In function 'bool cmp(const sHui&, const sHui&)':
/in/foo.cc:41:14: warning: self-comparison always evaluates to false [-Wtautological-compare]
    if(x.id[i]<x.id[i])
       ~~~~~~~^~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:57:36: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[23]' [-Wformat=]
   scanf("%s%s",&sh[i].id,&sh[i].num);
                ~~~~~~~~~           ^
/in/foo.cc:57:36: warning: format '%s' expects argument of type 'char*', but argument 3 has type 'char (*)[20000]' [-Wformat=]
/in/foo.cc: In function 'bool cmp(const sHui&, const sHui&)':
/in/foo.cc:50:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^