Compilare: main.cpp: In function 'int main()': main.cpp:13:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("spider-man.in", "r", stdin); ^ main.cpp:14:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("spider-man.out", "w", stdout); ^ main.cpp:15:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf %lf", &x_c, &y_c, &r); ^ main.cpp:16:53: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf %lf %lf", &x_A, &y_A, &x_B, &y_B); ^