foo.c: In function 'Concat':
foo.c:7:17: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
    7 |                 for (int i = 0; i < n; i++);
      |                 ^~~
foo.c:8:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
    8 |                 {
      |                 ^
foo.c:9:25: warning: statement with no effect [-Wunused-value]
    9 |                         for (m; s1[m] != '\0'; m++)
      |                         ^~~
foo.c:11:25: warning: statement with no effect [-Wunused-value]
   11 |                         for (n; s2[n] != '\0'; n++)
      |                         ^~~
foo.c:15:25: warning: statement with no effect [-Wunused-value]
   15 |                         for (n; s2[n] != '\0'; n++)
      |                         ^~~
foo.c: In function 'main':
foo.c:28:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
   28 |         gets(s1), gets(s2);
      |         ^~~~
In file included from foo.c:1:
/nix/store/linb70pgp53f0kygxm5wk163dx22d681-glibc-2.37-45-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
foo.c:28:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
   28 |         gets(s1), gets(s2);
      |         ^~~~
/nix/store/linb70pgp53f0kygxm5wk163dx22d681-glibc-2.37-45-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
/nix/store/3r87a2wq1w4l66wnsm7rqvy608mx23h6-binutils-2.40/bin/ld: /tmp/ccMAibJD.o: in function `main':
foo.c:(.text.startup+0x1e): warning: the `gets' function is dangerous and should not be used.

[Hydro](https://hydro.ac)提供评测服务