Compilare: user.cpp: In function ‘int main()’: user.cpp:16:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[c] = 1 - f[c]; ^ user.cpp:16:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[c] = 1 - f[c]; ^ user.cpp: In function ‘bool op()’: user.cpp:57:19: warning: array subscript has type ‘char’ [-Wchar-subscripts] r = f[s[i]], ++i; ^ user.cpp: In function ‘int main()’: user.cpp:10:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.in", "r", stdin); ^ user.cpp:11:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.out", "w", stdout); ^ user.cpp:12:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s, 1001, stdin); ^ user.cpp:13:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:15:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &c); ^