You should spread it out and make it easier to understand. I find myself getting lost in embedded loops all the time. If you want, you can use this method:
Code:
#include <stdio.h>
int main (void)
{
int matrix[] = {0, 2, 2, 4, 0, 2, 2, 1, 8, 6, 0, 3};
int i, j, sum = 0;
for (i = 0; i < 12; i++)
{
switch (i % 4)
{
case 0:
sum += matrix[i] * 1000;
break;
case 1:
sum += matrix[i] * 100;
break;
case 2:
sum += matrix[i] * 10;
break;
case 3:
sum += matrix[i] * 1;
break;
}
}
printf("%d\n", sum);
return 0;
}