• Now that you have learnt about bitwise operators, you must have realized & is very different from &&. Similarily | is very different from ||
• & or | work on integers performing the operator on each corresponding bits. However, && or || work on boolean values ( Any non zero value is true ) to produce a boolean result.

Example :

   2  |   1  = 3
   2  ||  1  = true
   2   &  1  =  0
   2  &&  1  = true 

• Very similar to the fact that
  you can rewrite A = A + B as A += B,
  you can rewrite
  A = A | B as A |= B or
  A = A & B as A &= B