/in/foo.c: In function 'main':
/in/foo.c:8:13: warning: format '%s' expects argument of type 'char *', but argument 2 has type 'int *' [-Wformat=]
     scanf("%s%s",a,b);
            ~^    ~
            %ls
/in/foo.c:8:15: warning: format '%s' expects argument of type 'char *', but argument 3 has type 'int *' [-Wformat=]
     scanf("%s%s",a,b);
              ~^    ~
              %ls
/in/foo.c:11:16: warning: passing argument 1 of 'strcat' from incompatible pointer type [-Wincompatible-pointer-types]
         strcat(b,a);
                ^
In file included from /in/foo.c:2:0:
/usr/include/string.h:133:14: note: expected 'char * restrict' but argument is of type 'int *'
 extern char *strcat (char *__restrict __dest, const char *__restrict __src)
              ^~~~~~
/in/foo.c:11:18: warning: passing argument 2 of 'strcat' from incompatible pointer type [-Wincompatible-pointer-types]
         strcat(b,a);
                  ^
In file included from /in/foo.c:2:0:
/usr/include/string.h:133:14: note: expected 'const char * restrict' but argument is of type 'int *'
 extern char *strcat (char *__restrict __dest, const char *__restrict __src)
              ^~~~~~
/in/foo.c:12:16: warning: passing argument 1 of 'strcat' from incompatible pointer type [-Wincompatible-pointer-types]
         strcat(a,b);
                ^
In file included from /in/foo.c:2:0:
/usr/include/string.h:133:14: note: expected 'char * restrict' but argument is of type 'int *'
 extern char *strcat (char *__restrict __dest, const char *__restrict __src)
              ^~~~~~
/in/foo.c:12:18: warning: passing argument 2 of 'strcat' from incompatible pointer type [-Wincompatible-pointer-types]
         strcat(a,b);
                  ^
In file included from /in/foo.c:2:0:
/usr/include/string.h:133:14: note: expected 'const char * restrict' but argument is of type 'int *'
 extern char *strcat (char *__restrict __dest, const char *__restrict __src)
              ^~~~~~
/in/foo.c:14:18: warning: format '%s' expects argument of type 'char *', but argument 2 has type 'int *' [-Wformat=]
         printf("%s",a);
                 ~^  ~
                 %ls
/in/foo.c:6:35: warning: unused variable 'k' [-Wunused-variable]
     int a[100000],b[100000],n,m=1,k=0;
                                   ^