老师改小测验，answers 里 true 是答对，false 是答错。mark 用两个引用参数 right、wrong 带回对了几题、错了几题。写循环里面。没有题目时两个都是 0。
quiz_result({true, true, false, true})→'3 right, 1 wrong'quiz_result({})→'0 right, 0 wrong'string quiz_result(const vector<bool> &answers)#include <string>
#include <vector>
using namespace std;
void mark(const vector<bool> &answers, int &right, int &wrong) {
right = 0;
wrong = 0;
for (bool ok : answers) {
// 在这里写：对了 right 加 1，错了 wrong 加 1
}
}
string quiz_result(const vector<bool> &answers) {
int right = 0, wrong = 0;
mark(answers, right, wrong);
return to_string(right) + " right, " + to_string(wrong) + " wrong";
}
写好了先点「运行」试试示例，没问题再点「提交」。