Compilare: user.cpp: In function ‘int main()’: user.cpp:54:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("online.in","r",stdin); ^ user.cpp:55:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("online.out","w",stdout); ^ user.cpp:57:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:59:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &u[i].x, &u[i].y, &u[i].c); ^ user.cpp:64:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &f); ^ user.cpp:66:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &u[m+i].x, &u[m+i].y, &u[m+i].c); ^