Question

//arrays modulus and modrog

byte[] modulus ={-30, 0 , 25, 70,-25,-3,-2};  
byte[] modorg=new byte[7];

//the loop that counts the elements

for (int j = 0; j < modulus.length; j++)
{
    if (modulus[j] < 0)
    {
        modorg[j] = (byte) ((int)modulus[j] + 256);
    }
    else
    {
        modorg[j]=modorg[j];
    }
}

Answer 1

Adding 256 to a byte is like adding 360 to a degree 🙂
You will get the same value.
You probably want to add 128?