/in/foo.cc: In function 'void compear(int, int)':
/in/foo.cc:8:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define f(i,a,b) for(int i=a;i<=b;i++)
                                
/in/foo.cc:19:4:
  f(i,0,max(strlen(st[a]),strlen(st[b]))){
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:19:2: note: in expansion of macro 'f'
  f(i,0,max(strlen(st[a]),strlen(st[b]))){
  ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:41:6: warning: unused variable 'a' [-Wunused-variable]
  int a,b,c;
      ^