Compilare: user.cpp: In function ‘int main()’: user.cpp:21:19: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (b[i] != a[j]) ++j; ^ user.cpp:21:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (b[i] != a[j]) ++j; ^ user.cpp:11:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sr.in", "r", stdin); ^ user.cpp:12:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sr.out", "w", stdout); ^ user.cpp:14:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a + 1); ^ user.cpp:15:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(b + 1); ^ /tmp/cc0lMWJj.o: In function `main': user.cpp:(.text.startup+0x54): warning: the `gets' function is dangerous and should not be used.