Compilare: main.cpp: In function 'void readNumber()': main.cpp:72:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s.length() && s[i] >= '0' && s[i] <= '9') ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:103:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s.length()) ~~^~~~~~~~~~~~ main.cpp:98:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.in", "r", stdin); ^ main.cpp:99:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.out", "w", stdin); ^