/in/foo.c: In function 'main':
/in/foo.c:6:10: warning: format '%s' expects argument of type 'char *', but argument 2 has type 'char (*)[100]' [-Wformat=]
  scanf("%s",&a);
         ~^  ~~
/in/foo.c:7:10: warning: variable 'n' set but not used [-Wunused-but-set-variable]
  int i,m,n;
          ^
/in/foo.c:7:8: warning: 'm' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int i,m,n;
        ^