Fill Matrix in a special order C++ - c++

Question

I want to fill a 8 x 8 matrix with values in a special order (see example below), but I don´t know how to do that. Each numer stands for the ordering number: For example: #3 in the matrix is the third value of a e.g. a measurment I want to add.
The Order should be:
1 2 5 6 17 18 21 22
3 4 7 8 19 20 23 24
9 10 13 14 25 26 29 30
11 12 15 16 27 28 31 32
33 34 37 38 49 50 53 54
35 36 39 40 51 52 55 56
41 42 45 46 57 58 61 62
43 44 47 48 59 60 63 64
Does anybody knows an algorithmus to do that?
I have tried this, but that´s not a good way to to it, and it´s not working for the whole matrix
int b= 0, ii = 0, a = 0, iii = 0
i are different measurement values
and now a for loop
if (ii == 1)
{
b++;
}
if (ii == 2)
{
a++, b--;
}
if (ii == 3)
{
b ++;
}
tempMatrix[a][b] = i;
cout << "TempMatrix " << tempMatrix[a][b] << " a " << a << " b " << b << endl;
if (ii == 3)
{
ii = -1;
a --;
b ++;
}
if (iii == 7)
{
a = a + 2;
b = 0;
iii = -1;
}

Answer 1

Use recursion:
#include <iostream>
using namespace std;
void f(int a[8][8], int current, int x, int y, int size) {
if (size == 1) {
a[x][y] = current;
return;
} else {
size /= 2;
int add_for_each_square = size * size;
f(a, current, x, y, size);
f(a, current + add_for_each_square, x, y + size, size);
f(a, current + 2 * add_for_each_square, x + size, y, size);
f(a, current + 3 * add_for_each_square, x + size, y + size, size);
}
}
int main() {
int a[8][8];
f(a, 1, 0, 0, 8);
for (int i = 0; i < 8; ++i) {
for (int j = 0; j < 8; ++j) {
cout << a[i][j] << " ";
}
cout << endl;
}
}

Answer 2

If the matrix will always be a fixed size, then you can generate two lookup tables for row and column indexes into the matrix. Then, just pass your index through these tables to get the desired positions in the matrix.
const auto MATRIX_SIZE = 8;
const std::array<int, MATRIX_SIZE*MATRIX_SIZE> row_lookup = {{...}}; //put pre-computed values here.
const std::array<int, MATRIX_SIZE*MATRIX_SIZE> col_lookup = {{...}};
for(size_t i = 0; i < MATRIX_SIZE * MATRIX_SIZE; i++)
{
auto val = get_coefficient(i);
auto row = row_lookup[i];
auto col = col_lookup[i];
mat[col][row] = val;
}