选择结构

#include<iostream>


using namespace std;
int main()
{
 int x;
 cin>> x;
 if (x>=80 && x<=100) cout<<"A";
 if (x>=70 && x<=80) cout<<"B";
 if (x>=60 && x<=70) cout<<"C";
 if (x>=00 && x<=60) cout<<"D";
 else cout<<"E";
 return 0;
}