条件表达式写长了基本上看不懂，还不如写if-else语句。不过2层以内还是看起来不错的。

#include<iostream>
#include<vector>
using namespace std;

int main()
{
	int grade = 70;
	string finalGrade = (grade < 60) ? "fail" : "pass";
	cout << finalGrade << endl;

	finalGrade = (grade > 90) ? "high pass" : (grade < 60) ? "fail" : "pass";
	cout << finalGrade << endl;

	return 0;
}

结果：

pass
pass