Câu 1:
#include <bits/stdc++.h>
using namespace std;
int main() {
int n,t,na;
cout<<"Nhap ngay, thang, nam: "; cin>>n>>t>>na;
cout<<n<<"/"<<t<<"/"<<na<<endl;
}
Câu 2:
#include <bits/stdc++.h>
using namespace std;
int main() {
float r;
cout<<"Nhap ban kinh duong tron: "; cin>>r;
cout<<"Chu vi: "<<setprecision(1)<<fixed<<r*2*3.14<<endl;
cout<<"Dien tich: "<<setprecision(1)<<fixed<<r*r*3.14<<endl;
}