Compilare: main.cpp: In function 'int main()': main.cpp:21:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0;j<=b.size();j++){ ~^~~~~~~~~~ main.cpp:24:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1;i<=a.size();i++){ ~^~~~~~~~~~ main.cpp:25:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=1;j<=b.size();j++){ ~^~~~~~~~~~ main.cpp:16:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("subsir.in","r",stdin); ^ main.cpp:17:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("subsir.out","w",stdout); ^