5.3.1节练习

练习5.5

#include <iostream>  #include <string>#include <vector>using namespace std;int main(){const vector<string> lev = { "A++", "A", "B", "C", "D", "F" ,"成绩无效"};vector<int> scores;vector<string> ltrscr;int a = 0;string b = "";while (cin>>a)scores.push_back(a);for (const auto i : scores){if (i<0||i>100)ltrscr.push_back(lev[6]);else if (i < 60)ltrscr.push_back(lev[5]);else if (i < 70)ltrscr.push_back(lev[4]);else if (i<80)ltrscr.push_back(lev[3]);else if (i<90)ltrscr.push_back(lev[2]);else if (i<100)ltrscr.push_back(lev[1]);else ltrscr.push_back(lev[0]);}for (unsigned j = 0; j != scores.size(); j++)cout << scores[j] << " " << ltrscr[j] << endl;system("pause");return 0;}