Compilare: main.cpp: In function 'int main()': main.cpp:105:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<v1.size();++i) ~^~~~~~~~~~ main.cpp:121:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<v2.size();++i) ~^~~~~~~~~~ main.cpp: In function 'int read()': main.cpp:60:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&ch); ^ main.cpp: In function 'int main()': main.cpp:72:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rays.in","r",stdin); ^ main.cpp:73:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rays.out","w",stdout); ^