《c++编程思想第2卷》第四章练习题4-15答案

最近在看c++编程思想第2卷，今天刚刚做完了第4章输入输出流的练习题，觉得第15题有点意思，特写到博文里，以便以后查阅和学习。

题目如下：（意思是解析文件，并按格式输出）

15.    Suppose you are given line-oriented data in a file formatted as follows:
//: C04:Exercise15.txt
Australia
5E56,7667230284,Langler,Tyson,31.2147,0.00042117361
2B97,7586701,Oneill,Zeke,553.429,0.0074673053156065
4D75,7907252710,Nickerson,Kelly,761.612,0.010276276
9F2,6882945012,Hartenbach,Neil,47.9637,0.0006471644
Austria
480F,7187262472,Oneill,Dee,264.012,0.00356226040013
1B65,4754732628,Haney,Kim,7.33843,0.000099015948475
DA1,1954960784,Pascente,Lester,56.5452,0.0007629529
3F18,1839715659,Elsea,Chelsy,801.901,0.010819887645
Belgium
BDF,5993489554,Oneill,Meredith,283.404,0.0038239127
5AC6,6612945602,Parisienne,Biff,557.74,0.0075254727
6AD,6477082,Pennington,Lizanne,31.0807,0.0004193544
4D0E,7861652688,Sisca,Francis,704.751,0.00950906238
Bahamas
37D8,6837424208,Parisienne,Samson,396.104,0.0053445
5E98,6384069,Willis,Pam,90.4257,0.00122009564059246
1462,1288616408,Stover,Hazal,583.939,0.007878970561
5FF3,8028775718,Stromstedt,Bunk,39.8712,0.000537974
1095,3737212,Stover,Denny,3.05387,0.000041205248883
7428,2019381883,Parisienne,Shane,363.272,0.00490155
///:~
 

The heading of each section is a region, and every line under that heading is a seller in that region. Each comma-separated field represents the data about each seller. The first field in a line is the SELLER_ID which unfortunately was written out in hexadecimal format. The second is the PHONE_NUMBER (notice that some are missing area codes). LAST_NAME and FIRST_NAME then follow. TOTAL_SALES is the second to the last column. The last column is the decimal amount of the total sales that the seller represents for the company. You are to format the data on the terminal window so that an executive can easily interpret the trends. Sample output is given below.

                          Australia

              ---------------------------------

 

*Last Name*  *First Name*   *ID*    *Phone*        *Sales*   *Percent*

 

Langler       Tyson          24150   766-723-0284     31.24   4.21E-02

Oneill        Zeke           11159   XXX-758-6701    553.43   7.47E-01

(etc.)

本人实现代码为：

/* * 415.cpp * *  Created on: Aug 14, 2015 *      Author: zyl */#include <fstream>#include <string>#include <iostream>#include <iomanip>#include <sstream>#include "../require.h"using namespace std;class Sales_man {size_t id;string last_name, first_name;string phone;double sales;double percent;public:enum {NAME_LENGTH = 12, ID_LENGTH = 5, PHONE_LENGTH = 12,SALES_LENGTH = 8, PERCENT_LENGTH = 7};friend ostream& operator<<(ostream& os, const Sales_man& sales_man);friend istream& operator>>(istream& is, Sales_man& sales_man);};ostream& operator<<(ostream& os, const Sales_man& sales_man) {char fillc = os.fill(' ');streamsize prec = os.precision();os << left << setw(Sales_man::NAME_LENGTH) << sales_man.last_name << " "   << setw(Sales_man::NAME_LENGTH) << sales_man.first_name << " "   << setw(Sales_man::ID_LENGTH) << sales_man.id << " "   << setw(Sales_man::PHONE_LENGTH) << sales_man.phone << " "   << right << setw(Sales_man::SALES_LENGTH) << setprecision(2) << sales_man.sales << " "   << right << setw(Sales_man::PERCENT_LENGTH) << setprecision(2) << scientific << sales_man.percent   << left;os.fill(fillc);os.precision(prec);return os;}istream& operator>>(istream& is, Sales_man& sales_man) {char comma;is >> hex >> sales_man.id;is >> comma;char phone[255];is.get(phone, sizeof(phone), ',');// add '-' into phonesales_man.phone = phone;sales_man.phone.insert(3, "-");sales_man.phone.insert(7, "-");is >> comma;char lastname[255];is.get(lastname, sizeof(lastname), ',');sales_man.last_name = lastname;is >> comma;is.get(lastname, sizeof(lastname), ',');sales_man.first_name = lastname;is >> comma;is >> sales_man.sales;is >> comma;is >> sales_man.percent;return is;}bool startsWith(const string&line, const string& start) {size_t pos = line.find(start);if (pos == 0) {return true;}return false;}void printTitle(ostream& os) {char fillc = os.fill(' ');streamsize prec = os.precision();os << left << setw(Sales_man::NAME_LENGTH) << "*Last Name*" <<" "   << setw(Sales_man::NAME_LENGTH) << "*First Name*" <<" "   << setw(Sales_man::ID_LENGTH) << "*ID*"<< " "   << setw(Sales_man::PHONE_LENGTH) << "*Phone*" <<" "   << right << setw(Sales_man::SALES_LENGTH) << "*Sales*" << " "   << right << setw(Sales_man::PERCENT_LENGTH) << "*Percent*" <<" "   << left;os.fill(fillc);os.precision(prec);}int main() {ifstream ifs("Exercise15.txt");assure(ifs);string line;while (getline(ifs, line)) {// jump the comment lineif (startsWith(line, "//")) {continue;}istringstream is(line);size_t pos = line.find(",");if (pos == string::npos) {//it's country linecout << "                    " << line << endl;cout << "               --------------------" << endl;printTitle(cout);cout << endl << endl;} else {Sales_man man;is >> man;cout << man << endl;}}}