/in/foo.cc: In function 'int main()':
/in/foo.cc:45:26: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[25]' [-Wformat=]
   scanf("%s/n",&stu[i].xh);
                          ^
/in/foo.cc: In function 'bool comp1(st, st)':
/in/foo.cc:19:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'bool comp2(st, st)':
/in/foo.cc:39:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^