Compilare: main.cpp: In function 'int main()': main.cpp:32:12: warning: unused variable 'u1' [-Wunused-variable] double u1,u2; ^~ main.cpp:32:15: warning: unused variable 'u2' [-Wunused-variable] double u1,u2; ^~ main.cpp:29:33: 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:30:35: 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); ^ main.cpp:33:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:36:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y1,&y2); ^