[英]C++ Multidimensional Vector
how can I make a table like this with vector in C++: 如何在C ++中使用vector制作这样的表:
65 A
66 B
67 C
I did it with a dynamic 2d array like this: 我是用这样的动态2D数组完成的:
int** ary = new int*[2];
for (int i = 0; i < size; ++i)
ary[i] = new int[size];
// fill the array
for (int i = 0; i < size; i++) {
ary[i][0] = ascii_values[i];
}
for (int i = 0; i < size; i++) {
ary[i][1] = ascii_chars[i];
}
How can I do this with vector? 我该如何使用vector? I was thinking of putting two vectors inside a third vector but I don`t know if that is possible.
我当时正在考虑将两个向量放在第三个向量中,但是我不知道这是否可行。 Ps everything has to be dynamic because I will import data from a file Please help :)
PS一切都必须是动态的,因为我将从文件中导入数据,请帮助:)
Your data is actually not really multidimensional, but rather a list of int, char
pairs. 您的数据实际上并不是真正的多维数据,而是
int, char
对的列表。 Thus the most natural would be a std::vector<std::pair<int,char>>
. 因此,最自然的将是
std::vector<std::pair<int,char>>
。 Imho whenever you can name a pair, you should do so, ie that would be 恕我直言,只要您可以命名一对,就应该这样做,即
struct Foo { // I cannot, but you can choose better names
int x;
char y;
};
And create a vector via 并通过创建向量
std::vector<Foo> f;
For how to use a vector I refer you to the massive amount of material that you can find online. 有关如何使用向量的信息,请参考网上可以找到的大量材料。
If however, you already have your data in two vectors, as you mentioned in a comment, then the easiest is probably to use some 但是,如果您已经在注释中提到过,您已经将数据分为两个向量,那么最简单的方法就是使用一些
struct Bar {
std::vector<char> x;
std::vector<int> y;
};
which may contain the same data, but depending on how you need to process the data it might be more or less efficient compared to the std::vector<Foo>
(do you need to access the chars and ints independently or always as those pairs?). 其中可能包含相同的数据,但是取决于您需要如何处理数据,与
std::vector<Foo>
相比,效率可能更高或更低(您是否需要独立或始终以成对的方式访问char和int ?)。
You can easily implement the behaviour above using a vector of std::pair
. 您可以使用
std::pair
向量轻松实现上述行为。 See the demo : 观看演示 :
#include <utility>
#include <vector>
#include <algorithm>
#include <iostream>
int main() {
std::vector<std::pair<int,char>> result;
std::vector<int> ascii_vals {65, 66, 67};
std::vector<char> ascii_chars {'a', 'b', 'c'};
auto ItA = ascii_vals.begin();
auto ItB = ascii_chars.begin();
while(ItA != ascii_vals.end() && ItB != ascii_chars.end())
{
result.push_back(std::make_pair(*ItA,*ItB));
if(ItA != ascii_vals.end())
{
++ItA;
}
if(ItB != ascii_chars.end())
{
++ItB;
}
}
for(std::vector<std::pair<int, char> >::iterator it = result.begin(); it != result.end(); it++)
std::cout << "(" << it->first << ", " << it->second << ")" << std::endl;
return 0;
}
The code above will print: 上面的代码将打印:
(65, a)
(66, b)
(67, c)
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