有一件事我认为在之前的回答中没有提到。

当人们在设计中使用这些东西时，我总是感觉到重构的“臭味”。

这是一个巨大的数组，从效率和性能的角度来看，这可能不是表示数据的最佳方式。

欢呼,

Rob

前面已经指出，数组大小受硬件和操作系统的限制(man ulimit)。不过，你的软件可能只受限于你的创造力。例如，您可以将“数组”存储在磁盘上吗?你真的需要长整型吗?你真的需要密集数组吗?你需要数组吗?

One simple solution would be to use 64 bit Linux. Even if you do not physically have enough ram for your array, the OS will allow you to allocate memory as if you do since the virtual memory available to your process is likely much larger than the physical memory. If you really need to access everything in the array, this amounts to storing it on disk. Depending on your access patterns, there may be more efficient ways of doing this (ie: using mmap(), or simply storing the data sequentially in a file (in which case 32 bit Linux would suffice)).

有一件事我认为在之前的回答中没有提到。

当人们在设计中使用这些东西时，我总是感觉到重构的“臭味”。

这是一个巨大的数组，从效率和性能的角度来看，这可能不是表示数据的最佳方式。

欢呼,

Rob

我会通过创建一个2d动态数组来解决这个问题:

long long** a = new long long*[x];
for (unsigned i = 0; i < x; i++) a[i] = new long long[y];

更多信息请访问https://stackoverflow.com/a/936702/3517001

我很惊讶std::vector的max_size()成员函数在这里没有提到。

返回由于系统或库实现限制，容器能够容纳的最大元素数，即对于最大的容器std::distance(begin()， end())。

我们知道std::vector在底层是作为一个动态数组实现的，因此max_size()应该给出与您机器上动态数组的最大长度非常接近的值。

下面的程序为各种数据类型构建一个近似最大数组长度的表。

#include <iostream>
#include <vector>
#include <string>
#include <limits>

template <typename T>
std::string mx(T e) {
    std::vector<T> v;
    return std::to_string(v.max_size());
}

std::size_t maxColWidth(std::vector<std::string> v) {
    std::size_t maxWidth = 0;

    for (const auto &s: v)
        if (s.length() > maxWidth)
            maxWidth = s.length();

    // Add 2 for space on each side
    return maxWidth + 2;
}

constexpr long double maxStdSize_t = std::numeric_limits<std::size_t>::max();

// cs stands for compared to std::size_t
template <typename T>
std::string cs(T e) {
    std::vector<T> v;
    long double maxSize = v.max_size();
    long double quotient = maxStdSize_t / maxSize;
    return std::to_string(quotient);
}

int main() {
    bool v0 = 0;
    char v1 = 0;

    int8_t v2 = 0;
    int16_t v3 = 0;
    int32_t v4 = 0;
    int64_t v5 = 0;

    uint8_t v6 = 0;
    uint16_t v7 = 0;
    uint32_t v8 = 0;
    uint64_t v9 = 0;

    std::size_t v10 = 0;
    double v11 = 0;
    long double v12 = 0;

    std::vector<std::string> types = {"data types", "bool", "char", "int8_t", "int16_t",
                                      "int32_t", "int64_t", "uint8_t", "uint16_t",
                                      "uint32_t", "uint64_t", "size_t", "double",
                                      "long double"};

    std::vector<std::string> sizes = {"approx max array length", mx(v0), mx(v1), mx(v2),
                                      mx(v3), mx(v4), mx(v5), mx(v6), mx(v7), mx(v8),
                                      mx(v9), mx(v10), mx(v11), mx(v12)};

    std::vector<std::string> quotients = {"max std::size_t / max array size", cs(v0),
                                          cs(v1), cs(v2), cs(v3), cs(v4), cs(v5), cs(v6),
                                          cs(v7), cs(v8), cs(v9), cs(v10), cs(v11), cs(v12)};

    std::size_t max1 = maxColWidth(types);
    std::size_t max2 = maxColWidth(sizes);
    std::size_t max3 = maxColWidth(quotients);

    for (std::size_t i = 0; i < types.size(); ++i) {
        while (types[i].length() < (max1 - 1)) {
            types[i] = " " + types[i];
        }

        types[i] += " ";

        for  (int j = 0; sizes[i].length() < max2; ++j)
            sizes[i] = (j % 2 == 0) ? " " + sizes[i] : sizes[i] + " ";

        for  (int j = 0; quotients[i].length() < max3; ++j)
            quotients[i] = (j % 2 == 0) ? " " + quotients[i] : quotients[i] + " ";

        std::cout << "|" << types[i] << "|" << sizes[i] << "|" << quotients[i] << "|\n";
    }

    std::cout << std::endl;

    std::cout << "N.B. max std::size_t is: " <<
        std::numeric_limits<std::size_t>::max() << std::endl;

    return 0;
}

在我的macOS (clang版本5.0.1)上，我得到了以下结果:

|  data types | approx max array length | max std::size_t / max array size |
|        bool |   9223372036854775807   |             2.000000             |
|        char |   9223372036854775807   |             2.000000             |
|      int8_t |   9223372036854775807   |             2.000000             |
|     int16_t |   9223372036854775807   |             2.000000             |
|     int32_t |   4611686018427387903   |             4.000000             |
|     int64_t |   2305843009213693951   |             8.000000             |
|     uint8_t |   9223372036854775807   |             2.000000             |
|    uint16_t |   9223372036854775807   |             2.000000             |
|    uint32_t |   4611686018427387903   |             4.000000             |
|    uint64_t |   2305843009213693951   |             8.000000             |
|      size_t |   2305843009213693951   |             8.000000             |
|      double |   2305843009213693951   |             8.000000             |
| long double |   1152921504606846975   |             16.000000            |

N.B. max std::size_t is: 18446744073709551615

在ideone gcc 8.3我得到:

|  data types | approx max array length | max std::size_t / max array size |
|        bool |   9223372036854775744   |             2.000000             |
|        char |   18446744073709551615  |             1.000000             |
|      int8_t |   18446744073709551615  |             1.000000             |
|     int16_t |   9223372036854775807   |             2.000000             |
|     int32_t |   4611686018427387903   |             4.000000             |
|     int64_t |   2305843009213693951   |             8.000000             |
|     uint8_t |   18446744073709551615  |             1.000000             |
|    uint16_t |   9223372036854775807   |             2.000000             |
|    uint32_t |   4611686018427387903   |             4.000000             |
|    uint64_t |   2305843009213693951   |             8.000000             |
|      size_t |   2305843009213693951   |             8.000000             |
|      double |   2305843009213693951   |             8.000000             |
| long double |   1152921504606846975   |             16.000000            |

N.B. max std::size_t is: 18446744073709551615

需要注意的是，这是一个理论上的限制，在大多数计算机上，您将在达到这个限制之前耗尽内存。例如，对于gcc上的char类型，最大元素数等于std::size_t的最大值。尝试这个，我们得到错误:

prog.cpp: In function ‘int main()’:
prog.cpp:5:61: error: size of array is too large
  char* a1 = new char[std::numeric_limits<std::size_t>::max()];

最后，正如@MartinYork指出的，对于静态数组，最大大小受限于堆栈的大小。

To summarize the responses, extend them, and to answer your question directly: No, C++ does not impose any limits for the dimensions of an array. But as the array has to be stored somewhere in memory, so memory-related limits imposed by other parts of the computer system apply. Note that these limits do not directly relate to the dimensions (=number of elements) of the array, but rather to its size (=amount of memory taken). Dimensions (D) and in-memory size (S) of an array is not the same, as they are related by memory taken by a single element (E): S=D * E. Now E depends on:

数组元素的类型(元素可以更小也可以更大) 内存对齐(为了提高性能，元素被放置在某个值的倍数的地址上，这会引入 元素之间的“浪费空间”(填充) 对象静态部分的大小(在面向对象编程中，相同类型对象的静态组件只存储一次，与此类相同类型对象的数量无关)

Also note that you generally get different memory-related limitations by allocating the array data on stack (as an automatic variable: int t[N]), or on heap (dynamic alocation with malloc()/new or using STL mechanisms), or in the static part of process memory (as a static variable: static int t[N]). Even when allocating on heap, you still need some tiny amount of memory on stack to store references to the heap-allocated blocks of memory (but this is negligible, usually). The size of size_t type has no influence on the programmer (I assume programmer uses size_t type for indexing, as it is designed for it), as compiler provider has to typedef it to an integer type big enough to address maximal amount of memory possible for the given platform architecture. The sources of the memory-size limitations stem from

进程可用的内存数量(对于32位应用程序，即使在64位操作系统内核上，也仅限于2^32字节)， 进程内存的划分(例如，为堆栈或堆设计的进程内存的数量)， 物理内存的碎片化(许多分散的小的空闲内存片段不适用于存储一个整体结构)， 物理内存的数量， 以及虚拟内存的数量。

They can not be ‘tweaked’ at the application level, but you are free to use a different compiler (to change stack size limits), or port your application to 64-bits, or port it to another OS, or change the physical/virtual memory configuration of the (virtual? physical?) machine. It is not uncommon (and even advisable) to treat all the above factors as external disturbances and thus as possible sources of runtime errors, and to carefully check&react to memory-allocation related errors in your program code. So finally: while C++ does not impose any limits, you still have to check for adverse memory-related conditions when running your code... :-)