How to define a pointer to a 2-dimesional array of pointers.

[ImLazy]

This code:

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#include <iostream>
using namespace std;
int main() {
    int a[2][3] = { {1, 2, 3}, {4, 5, 6} };
    int *(*b)[3];
    for (int i = 0; i < 2; i++)
        for (int j = 0; j < 3; j++)
            b[i][j] = &a[i][j];
    for (int i = 0; i < 2; i++)
        for (int j = 0; j < 3; j++)
            cout << *b[i][j] << " ";
    cout << endl;
    return 0;
};

I get this RUNTIME ERROR:

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Program received signal SIGSEGV, Segmentation fault.
0x0040147c in main () at test-p.cpp:8
8                   b[i][j] = &a[i][j];

I want each element of b[][] is a pointer to an element of a[][].

[mf]

int *(*b)[3]; is a pointer to an array of 3 pointers to int.
int *(*b)[3][3]; is a pointer to a 3x3 array of pointers to int.

There's a handy utility cdecl which can do this kinds of conversions between C and plain english for you. And when in doubt you can always use typedef to simplify declarations.

As for SIGSEGV, you should've allocated memory for this 3x3 array before accessing it (or else it points to nothing), and access it like (*b)[i][j].

[ImLazy]

, I forget to allocate memory for b.