Compilare: main.cpp: In function 'long long int nth()': main.cpp:17:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (s[p] != '\0' && s[p] != ')' && s[p] != ']' && p < s.size()) { ~~^~~~~~~~~~ main.cpp: In function 'long long int sums()': main.cpp:61:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (s[p] != '\0' && s[p] != ')' && s[p] != ']' && p < s.size()) { ~~^~~~~~~~~~ main.cpp: In function 'long long int solve()': main.cpp:96:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (s[p] != '\0' && s[p] != ')' && s[p] != ']' && p < s.size()) { ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:129:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("expresie2.in", "r", stdin); ^ main.cpp:130:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("expresie2.out", "w", stdout); ^