#include <iostream> //những số nguyên tố sẽ có dạng 6k+1 hoặc 6k-1 với k là số nguyên
using namespace std;//chú ý sao khi đã loại bỏ 2 số nguyên tố là 2 và 3 mới đúng
int main() {
int n;
float k1,k2;
cout<<"Nhap so n: "; cin>>n;
cout<<endl;
if(n<=3){
switch (n){
case 0:
case 1: cout<<"Khong la so nguyen to !!!"<<endl; break;
case 2: cout<<2<<" la so nguyen to !!!"<<endl; break;
case 3: cout <<3<<" la so nguyen to !!!"<<endl; break;
}
}
else{
k1=(n-1)/6.0;
if((k1-(int)k1)==0){
cout<<n<<" la so nguyen to!!!"<<endl;
}
else{
k2=(n+1)/6.0;
if((k2-(int)k2)==0){
cout<<n<<" la snt!!!"<<endl;
}
else{
cout<<n<<" khong la so nguyen to !!!"<<endl;
}
}
}
return 0;
}
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