Question

Hi I’m trying to construct a loop to execute 16 states of the 8 4 2 1 code in (C++)

   while( condition)
   {
   double Bubble[16], Bubble1[16];
        Bubble[0] = ( a-2 - (b-2) ) + ( c-2 - (d-2)); // represents 0000
        Bubble[1] = ( a-2 - (b-2) ) + ( c-2 - (d+2)); // represents 0001
        Bubble[2] = ( a-2 - (b-2) ) + ( c+2 - (d-2)); // represents 0010
        Bubble[3] = ( a-2 - (b-2) ) + ( c+2 - (d+2)); //represents 0011
    .......
        Bubble[15] =(a+2 - (b+2) ) + ( c+2 - (d+2)); //represents 1111
  }

Is there an easy way of coding using for loops? instead of writing bubble[] every time?
0 stands for -2 and 1 stands for +2. So I have 4 variables and each one need to be incremented and/or decremented. Can this be done using for loop?

Appreciate your help

Answer 1

I’m not totally sure what your code is doing, but you could rewrite it as follows:

for (int i = 0; i < 16; i++) {
  double a_value = (i & 0x8) ? a+2 : a-2;
  double b_value = (i & 0x4) ? b+2 : b-2;
  double c_value = (i & 0x2) ? c+2 : c-2;
  double d_value = (i & 0x1) ? d+2 : d-2;
  Bubble[i] = (a_value - b_value) + (c_value - d_value);
}