Compilare: user.cpp: In function ‘void read()’: user.cpp:27:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:29:81: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf %lf %lf", &a[i].st.x, &a[i].st.y, &a[i].dr.x, &a[i].dr.y); ^ user.cpp:31:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &f[i]); ^ user.cpp: In function ‘int main()’: user.cpp:119:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("laser.in", "r", stdin); ^ user.cpp:120:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("laser.out", "w", stdout); ^