A450.等级评测题解：

A450.等级评测

#include <bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    if(n<=59 && n>=0){
        cout << "E";
    }else if(n<=69){
        cout << "D";
    }else if(n<=79){
        cout << "C";
    }else if(n<=89){
        cout << "B";
    }else{
        cout << "A";
    }
    return 0;
}//用5个if解决！注意写的是else if！