如何在不使用指针的情况下将动态2d数组传递给函数？

I tried this but it is not working ! can any one help me please this is very important :(

我尝试了这个,但它没有用!任何人都可以帮助我,这是非常重要的:(

#include <iostream>
using namespace std;
int a[100][100];

void read(int a[][100],int n)
{
  int i,j;
  for(i=0;i<n;i++)
       for(j=0;j<n;j++)
     cin>>a[i][j];
}

int main ()
{
    int n;
    cin>>n;
    int a[n][n];
   read(a,n);
}

2 个解决方案

#1

The unclear syntax to pass array by reference is:

通过引用传递数组的不明确语法是:

void read(int (&a)[100][100], int n)

resulting in

#include <iostream>

void read(int (&a)[100][100], int n)
{
  for(int i = 0; i < n; i++)
       for(int j = 0; j < n; j++)
           std::cin >> a[i][j];
}

int main ()
{
    int n;
    std::cin >> n;
    int a[100][100];
    read(a, n);
}

but you might prefer std::vector:

但你可能更喜欢std :: vector:

#include <iostream>
#include <vector>

void read(std::vector<std::vector<int>> &mat)
{
    for (auto& v : mat) {
        for (auto& e : v) {
            std::cin >> e;
        }
    }
}

int main ()
{
    int n;
    std::cin >> n;
    std::vector<std::vector<int>> mat(n, std::vector<int>(n));
    read(mat);
}

#2

Since this is tagged C++. I'd like to suggest usage of std::vector. It's dynamic container which is very useful. You can resize it, clear it fill it with ease. Once you understand it's basic usage, they would come really handy in your future C++ development. I modified your code slightly:

因为这是标记的C ++。我想建议使用std :: vector。它是动态容器,非常有用。您可以调整它的大小,清除它可以轻松填充它。一旦你理解了它的基本用法,它们将在你未来的C ++开发中变得非常方便。我稍微修改了你的代码:

#include <iostream>
#include <vector>
using namespace std;

void read(vector<vector<int> >& arr,int n)
{
  int i,j;
  for(i=0;i<n;i++)
       for(j=0;j<n;j++)
           cin>>arr[i][j];
}
int main ()
{
    int N;
    cin>>N;
    vector<vector<int> > arr(N, vector<int>(N));
    read(arr, N);
}

They have many advantages over the primitive arrays like they can be initialized easily, suppose you want to initialize all to zero :

它们比原始数组有许多优点,比如它们可以很容易地初始化,假设你想要将所有数据初始化为零:

vector<vector<int> > arr(N, vector<int>(N, 0));

You don't have to worry about adding the array size whenever passing in functions. vector can easily handle this:

传入函数时,您不必担心添加数组大小。矢量可以轻松处理这个:

for(i = 0; i < arr.size(); i++) {
  for(j = 0; j < arr[i].size(); j++) {
    // do stuff
  }
}

Moreover with the added methods of the Standard template library like fill, swap. Many operations can be handled easily.

此外,添加了标准模板库的方法,如fill,swap。许多操作都可以轻松处理。

#1