蔡昀佑

#include<iostream>
using namespace std;
int main()
{
int score;
cout<<"輸入成績:";
cin>>score;
if(score>=180&&score<=100)
{
    cout<<"甲";
}else if(score>70&&score<=79)
{
    cout<<"乙";
}else if(score>60&&score<=69)
{
    cout<<"丙";  
}else if(score>0&&score<59)      
{
    cout<<"丁";
     
}else
{
    cout<<"X";
}
system("pause");
return 0;
}