【C++ Primer | 08】课后习题答案

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练习8.13

练习8.13

include <iostream> #include <sstream> #include <fstream> #include <string> #include <vector> using namespace std; struct PersonInfo { string name; vector<string> phones; }; bool valid(const string& str) { return isdigit(str[0]); } string format(const string& str) { return str.substr(0,3) + "-" + str.substr(3,3) + "-" + str.substr(6); } int main() { ifstream ifs("phonenumbers.txt"); if (!ifs) { cerr << "no phone numbers?" << endl; return -1; } string line, word; vector<PersonInfo> people; istringstream record; while (getline(ifs, line)) { PersonInfo info; record.clear(); record.str(line); record >> info.name; while (record >> word) info.phones.push_back(word); people.push_back(info); } for (const auto &entry : people) { ostringstream formatted, badNums; for (const auto &nums : entry.phones) if (!valid(nums)) badNums << " " << nums; else formatted << " " << format(nums); if (badNums.str().empty()) cout << entry.name << " " << formatted.str() << endl; else cerr << "input error: " << entry.name << " invalid number(s) " << badNums.str() << endl; } return 0; }