如何初始化 std::vector<std::time_t> 在构造函数初始值设定项列表中有 n 个元素</std::time_t>

Question

I am trying to initialize vector in constructor initializer list like so:

Foo::Foo()
    : vec{42}
{
    //  ...
}

The vector is declared as:

std::vector<std::time_t> vec;

Problem is that std::time_t is numeric type also, so instead of creating vector with 42 elements as I would like, it creates one element with stored value '42'.

Question: is there a way to initialize such vector with size in constructor initializer list?

Answer 1

When initialized with braced-init-list, the constructor of std::vector taking std::initializer_list is preferred; for vec{42} it would initialize vec as containing 1 element with value 42 .

You can apply parentheses initializer instead of braced-init-list (which is a C++11 feature).

Foo::Foo()
    : vec(42) // initialize vec as containing 42 default-initialized elements
{
    //  ...
}