Compilare: main.cpp: In function 'int next_phar(std::__cxx11::string)': main.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<exp.size();i++){ ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:143:35: 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); ^ main.cpp:144:37: 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); ^ main.cpp:147:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("\n%d\n", &n); ^