C++primer 11.2.3节练习解答11.12-11.14

C++primer 11.2.3节练习解答11.12-11.14

练习11.12：编写程序，读入string和int的序列，将每个string和int存入一个pair中，pair保存在一个vector中。

练习11.13：在上一题的程序中，至少有三种创建pair的方法。编写此程序的三个版本，分别采用不同的方法创建pair。解释你认为哪种形式最易于编写和理解，为什么？

练习11.14：扩展你在11.2.1节练习（第378页）中编写的孩子姓到名的map，添加一个pair的vector，保存孩子的名和生日。

#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <utility>

using namespace std;

//编写程序，读入string和int的序列，将每个string和int存入一个pair中，pair保存在一个vector中。
void exercise12()
{
string word;
int num;
vector<pair<string, int>> vecs;
cout << "please input a string: ";
while (cin>>word)
{
cout <<endl<< "please input a int: ";
cin >> num;
//vecs.push_back({ word, num });//特点是简洁
//vecs.push_back(make_pair(word, num));//特点是容易理解
vecs.push_back( pair<string, int>(word, num));//特点是易读
cout << endl << "continue ? Y/N: ";
char c = 'Y';
cin >> c;
if (c == 'N' || c == 'n')
break;
cout <<endl<< "please input a string: ";

}
for (const auto &vec : vecs)
cout << vec.first << " " << vec.second << endl;
}

//编写的孩子姓到名的map，添加一个pair的vector，保存孩子的名和生日。
void exercise14()
{
string family,name,birthday;
map<string, vector<pair<string, string>>> maps;
cout << "please input a family name: ";
while (cin >> family)
{
vector<pair<string, string>> vecs = {};
cout << endl << "please input a child name : ";
while (cin >> name)
{
cout << endl << "please input his birthday: ";
cin >> birthday;
vecs.push_back({ name, birthday });
cout << endl << "continue add child ? Y/N: ";
char c = 'Y';
cin >> c;
if (c == 'N' || c == 'n')
break;
cout << endl << "please input a child name : ";

}
maps[family] = vecs;

cout << endl << "continue add family ? Y/N: ";
char c = 'Y';
cin >> c;
if (c == 'N' || c == 'n')
break;
cout << endl << "please input a family name : ";

}
for (const auto &mapn : maps)
{
cout << mapn.first << endl;
for (const auto &vec : mapn.second)
cout << vec.first << " " << vec.second << ends;
cout << endl;
}

}

void main()
{
//exercise12();
exercise14();
}

ok ! Mark 一下第一篇 blog !