初始化二维std :: vector [英] Initializing a two dimensional std::vector

问题描述

所以，我有以下：

std::vector< std::vector <int> > fog;

我正在初始化它非常天真像：

and I am initializing it very naively like:

    for(int i=0; i<A_NUMBER; i++)
    {
            std::vector <int> fogRow;
            for(int j=0; j<OTHER_NUMBER; j++)
            {
                 fogRow.push_back( 0 );
            }
            fog.push_back(fogRow);
    }

它感觉很错了...还有另一种方法来初始化一个向量像这样？

And it feels very wrong... Is there another way of initializing a vector like this?

推荐答案

使用 std :: vector :: vector（count，value） 构造函数，接受初始大小和默认值：

Use the std::vector::vector(count, value) constructor that accepts an initial size and a default value:

std::vector<std::vector<int>> fog(
    A_NUMBER,
    std::vector<int>(OTHER_NUMBER)); // Defaults to zero initial value

如果值为其他零，例如 4 例如，必须为默认值：

If a value other zero, say 4 for example, was required to be the default then:

std::vector<std::vector<int>> fog(
    A_NUMBER,
    std::vector<int>(OTHER_NUMBER, 4));

仅仅提到在c ++ 11中引入的统一初始化，它允许初始化 vector 和其他容器，使用 {} ：

And just to mention uniform initialization introduced in c++11, which permits the initialization of vector, and other containers, using {}:

std::vector<std::vector<int>> fog { { 1, 1, 1 },
                                    { 2, 2, 2 } };

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