C++ 将动态大小的二维数组传递给函数 [英] C++ passing Dynamically-sized 2D Array to function

问题描述

我想弄清楚如何将动态构造的二维数组传递给函数.我知道必须指定列数，但就我而言，这取决于用户输入.

I'm trying to figure out how to pass 2D array, which is constructed dynamically to a function. I know that number of columns must be specified, but it my case it depends on user input.

有什么解决方法吗?

示例:

// Some function
void function(matrix[i][j]) {
// do stuff
}
// Main function
int N;
cout << "Size: ";
cin >> N;

int matrix[N][N];

for (int i=0;i<N;i++) { // 
 for (int j=0;j<N;j++) { 
  cin >> matrix[N][N];
 }
}

sort(matrix);

你明白了:)

推荐答案

如果您使用 C++，合理的选择是:

If you're on C++, the reasonable options are to:

• 使用 boost::multi_array(推荐)，或
• 制作您自己的二维数组类.好吧，您不必这样做，但在类中封装二维数组逻辑很有用，并且可以使代码变得干净.

手动二维数组索引如下所示:

Manual 2D array indexing would look like this:

void func(int* arrayData, int arrayWidth) {
    // element (x,y) is under arrayData[x + y*arrayWidth]
}

但是说真的，要么用一个类来包装它，要么享受 Boost 已经为您准备好了该类.手动索引这个很烦人，而且会使代码更不干净，更容易出错.

But seriously, either wrap this with a class or enjoy that Boost already has that class ready for you. Indexing this manually is tiresome and makes the code more unclean and error-prone.

编辑

http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html 表示 C99 为您提供了另一种解决方案:

http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html says that C99 has one more solution for you:

void func(int len, int array[len][len]) {
   // notice how the first parameter is used in the definition of second parameter
}

应该也适用于 C++ 编译器，但我从未使用过这种方法.

Should also work in C++ compilers, but I haven't ever used this approach.

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