这一道题非常简单，就是考察分支判断，用上if-else if- else语句就可以解决，废话不多说，上代码！

已AC，请放心食用

#include <iostream>
using namespace std;
int main()
{
    int score;
    cin >> score;
    if (score >= 90)
    {
        cout << "Excellent";
    }
    else if (score >= 80)
    {
        cout << "Good";
    }
    else if (score >= 60)
    {
        cout << "Pass";
    }
    else
    {
        cout << "Fail";
    }
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    if(n >= 90)
    {
        cout << "Excellent";
    }
    else if(n >= 80)
    {
        cout << "Good";
    }
    else if(n >= 60)
    {
        cout << "Pass";
    }
    else
    {
        cout << "Fail";
    }
    return 0;
}

#include <iostream>:
using namespace std;
int main()
{
    int n;
    cin >> n;
    if(n>=90)
    {
        cout << "Excellent";
    }
    else if(n>=80)
    {
        cout << "Good";
    }
    else if(n>=60)
    {
        cout << "Pass";
    }
    else
    {
        cout << "Fail";
    }
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int x;
    cin>>x;
    if (x>=90)
        cout<<"Excellent";
    else if (x>=80)
        cout<<"Good";
    else if (x>=60)
        cout<<"Pass";
    else
        cout<<"Fail";
    return 0;
}

这么简单，我先不做题解了。 (誰都会)