Compilare: user.cpp: In function ‘int main()’: user.cpp:63:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < elements.size(); ++ i) ^ user.cpp:23:26: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:37:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (str.clear(), scanf("%c", &c); c != '"'; scanf("%c", &c)) ^ user.cpp:37:4: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (str.clear(), scanf("%c", &c); c != '"'; scanf("%c", &c)) ^ user.cpp:45:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%c", &c); is_whitespace(c); scanf("%c", &c)); ^ user.cpp:45:4: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%c", &c); is_whitespace(c); scanf("%c", &c)); ^ user.cpp:48:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (str.clear(), scanf("%c", &c); c != '"'; scanf("%c", &c)) ^ user.cpp:48:5: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (str.clear(), scanf("%c", &c); c != '"'; scanf("%c", &c)) ^ user.cpp:51:5: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (str.clear(); c >= '0' && c <= '9'; scanf("%c", &c)) ^