c++ - 有没有办法在 for 循环中将多个变量 push_back 到一个 vector 中？

Question

例如使用保持变量推回 书籍(书名、作者、ISBN)

vector <Book> books;
Book book1("a", "Jim John", 1000);
Book book2("b", "Jim John", 1001);
Book book3("c", "Billy Bill", 1002);
Book book4("d", "Greg Lumburge", 1003);
Book book5("e", "Dallas Orange", 1004);
Book book6("f", "Old McDonald", 1005);

books.push_back(book1);
books.push_back(book2);
books.push_back(book3);
books.push_back(book4);
books.push_back(book5);
books.push_back(book6);

Answer 1

使用支持 C++11 标准的编译器，您可以使用 emplace_back，如下所示:

vector <Book> books;
books.emplace_back("a", "Jim John", 1000);
books.emplace_back("b", "Jim John", 1001);
books.emplace_back("c", "Billy Bill", 1002);
books.emplace_back("d", "Greg Lumburge", 1003);
books.emplace_back("e", "Dallas Orange", 1004);
books.emplace_back("f", "Old McDonald", 1005);

但更简单的是，使用 C++11，只需在花括号初始化程序中列出所有数据:

vector <Book> books =
{
    {"a", "Jim John", 1000},
    {"b", "Jim John", 1001},
    {"c", "Billy Bill", 1002},
    {"d", "Greg Lumburge", 1003},
    {"e", "Dallas Orange", 1004},
    {"f", "Old McDonald", 1005}
};

然后很容易添加一个const，如果合适的话。

---

在 C++03 中你可以这样做:

static Book const data[]    =
{
    Book("a", "Jim John", 1000),
    Book("b", "Jim John", 1001),
    Book("c", "Billy Bill", 1002),
    Book("d", "Greg Lumburge", 1003),
    Book("e", "Dallas Orange", 1004),
    Book("f", "Old McDonald", 1005)
};
int const data_size = sizeof( data )/sizeof( *data );

vector <Book> books( data, data + data_size );