c++ - 如何将一维数组更改为二维 vector ？

Question

我有一个一维数组{3,3,7,3,1,3,4,3,3,4,2,6,4,1,4,2,4,1} 我知道 vector 通常应该是 3*6 或 (m*n) 的阶数

{{3, 3, 7, 3, 1, 3},
 {4, 3, 3, 4, 2, 6},
 {4, 1, 4, 2, 4, 1}
}

我知道如何转换为二维数组，但我是 vector 的新手

int count =0;
for(int i=0;i<m;i++)
{
   for(int j=0;j<n;j++)
{
if(count==input.length)
   break;
a[i][j]=input[count];
count++;
}
}

Answer 1

本身并没有“2D vector ”这样的东西，但是你可以有一个 vector 的 vector 。

我认为这可以满足您的需求:

#include <vector>
#include <iostream>

using namespace std;


int main()
{
    // make a vector that contains 3 vectors of ints
    vector<vector<int>> twod_vector(3);

    int source[18] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17};
    for (int i = 0; i < 3; i++) {
        // get the i-th inner vector from the outer vector and fill it
        vector<int> & inner_vector = twod_vector[i];
        for (int j = 0; j < 6; j++) {
            inner_vector.push_back(source[6 * i + j]);
        }
    }

    // to show that it was properly filled, iterate through each
    //   inner vector
    for (const auto & inner_vector : twod_vector) {
        // in each inner vector, iterate through each integer it contains
        for (const auto & value : inner_vector) {
            cout << value;   
        }
        cout << endl;
    }

}

现场观看:http://melpon.org/wandbox/permlink/iqepobEY7lFIyKcX