foo.c: In function 'main':
foo.c:17:11: warning: array subscript has type 'char' [-Wchar-subscripts]
   17 |  while((s1[i]=getchar())!='\n')
      |           ^
foo.c:19:4: warning: array subscript has type 'char' [-Wchar-subscripts]
   19 |  s1[i]='\0';
      |    ^
foo.c:20:11: warning: array subscript has type 'char' [-Wchar-subscripts]
   20 |  while((s2[j]=getchar())!='\n')
      |           ^
foo.c:22:4: warning: array subscript has type 'char' [-Wchar-subscripts]
   22 |  s2[j]='\0';
      |    ^
foo.c: In function 'Concat':
foo.c:13:1: warning: control reaches end of non-void function [-Wreturn-type]
   13 | }
      | ^

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