Compilare: main.cpp: In function 'int main()': main.cpp:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<line.size(); i++) { ~^~~~~~~~~~~~ main.cpp:13:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("eq4.in", "r", stdin); ^ main.cpp:14:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("eq4.out", "w", stdout); ^