C++ 我可以在初始化列表中用 10 个相同整数初始化 STL 向量吗?

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时间:2020-08-27 13:46:27  来源:igfitidea点击:

Can I initialize an STL vector with 10 of the same integer in an initializer list?

c++stlconstructorinitializer-list

提问by Xavier

Can I initialize an STL vector with 10 of the same integer in an initializer list? My attempts so far have failed me.

我可以在初始化列表中用 10 个相同整数初始化 STL 向量吗?到目前为止,我的尝试都失败了。

采纳答案by David Rodríguez - dribeas

I think you mean this:

我想你的意思是:

struct test {
   std::vector<int> v;
   test(int value) : v( 100, value ) {}
};

回答by Ed S.

Use the appropriate constructor, which takes a size and a default value.

使用适当的构造函数,它接受一个大小和一个默认值。

int number_of_elements = 10;
int default_value = 1;
std::vector<int> vec(number_of_elements, default_value);

回答by Agus

The initialization list for vector is supported from C++0x. If you compiled with C++98

C++0x 支持向量的初始化列表。如果你用 C++98 编译

int number_of_elements = 10;
int default_value = 1;
std::vector<int> vec(number_of_elements, default_value);

回答by Mahmoud Al-Qudsi

If you're using C++11 and on GCC, you could do this:

如果您使用的是 C++11 和 GCC,您可以这样做:

vector<int> myVec () {[0 ... 99] = 1};

It's called ranged initialization and is a GCC-only extension.

它被称为范围初始化,是一个仅限 GCC 的扩展。

回答by Rafa? Rawicki

You can do that with std::vectorconstructor:

你可以用std::vector构造函数做到这一点:

vector(size_type count, 
                 const T& value,
                 const Allocator& alloc = Allocator());

Which takes countand valueto be repeated.

这需要countvalue重复。

If you want to use initializer lists you can write:

如果你想使用初始化列表,你可以写:

const int x = 5;
std::vector<int> vec {x, x, x, x, x, x, x, x, x, x};

回答by nate_weldon

can you post what you are doing

你能发布你在做什么吗

 int i = 100;
vector<int> vInts2 (10, i);

vector<int>::iterator iter;
for(iter = vInts2.begin(); iter != vInts2.end(); ++iter)
{
    cout << " i " << (*iter) << endl;
}