[英]initializing 2d vector using only 1 line c++
I need to be able to initialize a 2D vector of int's in the same line in which I create it. 我需要能够在创建它的同一行中初始化 int的2D向量。
To be more specific, I have to create a 3x2 size 2D vector and set all of it's values to 0 using only 1 line of code . 更具体地说,我必须创建3x2大小的2D向量,并仅使用1行代码即可将其所有值设置为0。
Is there a way this can be done without using a for loop and several lines of code? 有没有一种方法可以不使用for循环和几行代码来完成?
尝试这个:
std::vector<std::vector<int>> twoDimVector(3, std::vector<int>(2, 0));
If you have small 2d vectors (like as you suggested) it can be achieved (using brace-init ) quity easily. 如果您有较小的2d向量(如您所建议的),则可以很容易地(使用brace-init )实现它。
#include <vector>
#include <iostream>
int main(){
std::vector<std::vector<int>> vec{ { 0, 0 }, { 0, 0 }, { 0, 0 } };
std::cout << "vec size = " << vec.size() << "x" << vec[0].size() << std::endl;
return 0;
}
Output: 输出:
vec size = 3x2
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