Compilare: user.cpp: In function ‘int main()’: user.cpp:13:44: warning: format ‘%Lf’ expects argument of type ‘long double*’, but argument 3 has type ‘double*’ [-Wformat=] int N; scanf("%d %Lf %Lf", &N, &x0, &y0); ^ user.cpp:13:44: warning: format ‘%Lf’ expects argument of type ‘long double*’, but argument 4 has type ‘double*’ [-Wformat=] user.cpp:19:34: warning: format ‘%Lf’ expects argument of type ‘long double*’, but argument 2 has type ‘double*’ [-Wformat=] scanf("%Lf %Lf", &x2, &y2); ^ user.cpp:19:34: warning: format ‘%Lf’ expects argument of type ‘long double*’, but argument 3 has type ‘double*’ [-Wformat=] user.cpp:28:27: warning: format ‘%Lf’ expects argument of type ‘long double’, but argument 2 has type ‘double’ [-Wformat=] printf("%Lf", area / 2); ^ user.cpp:8:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.in", "r", stdin); ^ user.cpp:9:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.out", "w", stdout); ^ user.cpp:13:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int N; scanf("%d %Lf %Lf", &N, &x0, &y0); ^ user.cpp:19:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%Lf %Lf", &x2, &y2); ^