Compilare: user.cpp: In function ‘int main()’: user.cpp:2:159: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;long long d(int x){long long s(0);long long i(1);while(i*i<=x){s+=(x-i*(i-1))/i*2-1;++i;}return s;}int main(){freopen("ndiv.in","r",stdin);freopen("ndiv.out","w",stdout);long long a,b;scanf("%lld%lld",&a,&b);printf("%lld",d(b)-d(a-1));return 0;} ^ user.cpp:2:190: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;long long d(int x){long long s(0);long long i(1);while(i*i<=x){s+=(x-i*(i-1))/i*2-1;++i;}return s;}int main(){freopen("ndiv.in","r",stdin);freopen("ndiv.out","w",stdout);long long a,b;scanf("%lld%lld",&a,&b);printf("%lld",d(b)-d(a-1));return 0;} ^ user.cpp:2:228: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;long long d(int x){long long s(0);long long i(1);while(i*i<=x){s+=(x-i*(i-1))/i*2-1;++i;}return s;}int main(){freopen("ndiv.in","r",stdin);freopen("ndiv.out","w",stdout);long long a,b;scanf("%lld%lld",&a,&b);printf("%lld",d(b)-d(a-1));return 0;} ^