c++ std::pair 与 std::make_pair

转载：https://www.cnblogs.com/Nimeux/archive/2010/10/05/1844191.html

pair是一个结构体，其主要的两个成员变量是first和second，这两个变量可以直接使用。初始化一个pair可以使用构造函数，也可以使用std::make_pair函数

#include <iostream>
#include <utility>
#include <string>
using namespace std;

int main () {
  pair <string,double> product1 ("tomatoes",3.25);
  pair <string,double> product2;
  pair <string,double> product3;

  product2.first = "lightbulbs";     // type of first is string
  product2.second = 0.99;            // type of second is double

  product3 = make_pair ("shoes",20.0);

  cout << "The price of " << product1.first << " is $" << product1.second << "\n";
  cout << "The price of " << product2.first << " is $" << product2.second << "\n";
  cout << "The price of " << product3.first << " is $" << product3.second << "\n";
  return 0;
}