Compilare: user.cpp: In function ‘int main()’: user.cpp:82:33: warning: array subscript has type ‘char’ [-Wchar-subscripts] ++dif[rest][s[j]]; ^ user.cpp:67:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perb.in", "r", stdin); ^ user.cpp:68:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:69:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s + 1); ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:18:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^