Compilare: user.cpp: In function ‘int main()’: user.cpp:2:69: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int X,M;int main(){freopen("noroc.in","r",stdin);freopen("noroc.out","w",stdout);scanf("%d%d", &X, &M);printf("%.7f",max(1-(double)X/M,(double)0));return 0;} ^ user.cpp:2:101: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int X,M;int main(){freopen("noroc.in","r",stdin);freopen("noroc.out","w",stdout);scanf("%d%d", &X, &M);printf("%.7f",max(1-(double)X/M,(double)0));return 0;} ^ user.cpp:2:123: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int X,M;int main(){freopen("noroc.in","r",stdin);freopen("noroc.out","w",stdout);scanf("%d%d", &X, &M);printf("%.7f",max(1-(double)X/M,(double)0));return 0;} ^