Question

我在visual C ++中有一个2d字符串数组，如下所示：

static array<System::String ^, 2> ^messages = {
{"a", "b"},
{"c", "d", "e"},
{"f"},
};

我想像这样打印数据：

for(int i = 0; i < 3; i++)
     for(int j = 0; j < messages[i]->Length; j++)     //ERROR
                    //print messages[i, j]

我无法获得动态创建的数组的长度。我怎么能这样做？

Answer 1

你的意图并不完全清楚，但是如果你想为那种（;;）循环工作做出那样的话，你必须创建一个jagged array。一个数组数组，每个元素都是一个数组，而不是它自己的大小。

ref class Test {
    static array<array<String^>^>^ messages = {
        gcnew array<String^> {"a", "b"},
        gcnew array<String^> {"c", "d", "e" },
        gcnew array<String^> {"f" }
    };
public:
    static void Run() {
        for (int i = 0; i < messages->Length; i++) {
            for (int j = 0; j < messages[i]->Length; j++)
                Console::Write("{0} ", messages[i][j]);
            Console::WriteLine();
        }
    }
};

输出：

a b
c d e
f

Answer 2

array<System::String^, 2>声明了一个二维数组。以这种方式创建的阵列具有固定的高度和高度。宽度。

array<String^, 2>^ messages = 
{
    {"a", "b"},
    {"c", "d", "e"},
    {"f"},
};

Debug::WriteLine("The total number of array elements is {0}", messages->Length);
Debug::WriteLine("Dimension 0 has a length of {0}", messages->GetLength(0));
Debug::WriteLine("Dimension 1 has a length of {0}", messages->GetLength(1));

Debug::WriteLine("{");
for (int i = 0; i < messages->GetLength(0); i++)
{
    Debug::Write("    { ");
    for (int j = 0; j < messages->GetLength(1); j++)
    {
        Debug::Write("\"" + messages[i,j] + "\", ");
    }
    Debug::WriteLine("}");
}
Debug::WriteLine("}");

输出：

The total number of array elements is 9
Dimension 0 has a length of 3
Dimension 1 has a length of 3
{
    { "a", "b", "", }
    { "c", "d", "e", }
    { "f", "", "", }
}

但是，根据您初始化数组的方式以及循环方式，看起来您对锯齿状数组感兴趣，而不是常规二维（正方形/矩形））数组。这应该被声明为一个数组数组：每个内部数组都是单独初始化的，因此每个数组都有自己的长度。

array<array<String^>^>^ messages = 
{
    {"a", "b"},
    {"c", "d", "e"},
    {"f"},
};

// The only thing we can tell easily is the number of rows. The total 
// number of elements and the column count would require iteration.
Debug::WriteLine("There are {0} rows in the jagged array", messages->Length);

Debug::WriteLine("{");
for (int i = 0; i < messages->Length; i++)
{
    Debug::Write("    { ");
    for (int j = 0; j < messages[i]->Length; j++)
    {
        Debug::Write("\"" + messages[i][j] + "\", ");
    }
    Debug::WriteLine("}");
}
Debug::WriteLine("}");

输出：

There are 3 rows in the jagged array
{
    { "a", "b", }
    { "c", "d", "e", }
    { "f", }
}

动态创建数组的Visual C ++问题

2 个答案: