如何查找动态分配的数组的不同行的大小？

Question

I have the following code:

int *exceptions[7];
int a[] = {1, 4, 11, 13};
int b[] = {5, 6, 11, 12, 14, 15};
int c[] = {2, 12, 14, 15};
int d[] = {1, 4, 7, 9, 10, 15};
int e[] = {1, 3, 4, 5, 7, 9};
int f[] = {1, 2, 3, 7, 13};
int g[] = {0, 1, 7, 12};

exceptions[0] = a;
exceptions[1] = b;
exceptions[2] = c;
exceptions[3] = d;
exceptions[4] = e;
exceptions[5] = f;
exceptions[6] = g;

Size of exception[0] and exception[1] should be 4 and 6 respectively.

Here's my code:

short size = sizeof(exceptions[1]) / sizeof(exceptions[1][0]);

But I'm getting 2 for every row. How can I solve this problem?

Answer 1

 short size = sizeof(exceptions[1]) / sizeof(exceptions[1][0]);

effectively does the same as

 short size = sizeof(int*) / sizeof(int);

On a 64 bit platform, that yields most probably 2 .

---

How can I solve this problem?

Use some c++ standard container like std::vector<std::vector<int>> instead:

std::vector<std::vector<int>> exceptions {
    {1, 4, 11, 13},
    {5, 6, 11, 12, 14, 15},
    {2, 12, 14, 15},
    {1, 4, 7, 9, 10, 15},
    {1, 3, 4, 5, 7, 9},
    {1, 2, 3, 7, 13},
    {0, 1, 7, 12},
}

Your statement will become:

 short size = exceptions[0].size();
 size = exceptions[1].size();

(for whatever that's needed)

Answer 2

The best remedy would be to use vector provided in standard template library. They have a size() function which you can use and they are much more versatile than array.