【C++ Primer | 08】课后习题答案

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;
}