or statement in cpp code example

Example 1: how to write an or in c++

if (a == 0 || b == 0)
{
  //statement here, || was used as an or
}

Example 2: or in cpp

a || b = a or b

Example 3: x += c++

int main ()
{
  int a, b=3;
  a = b;
  a+=2;             // equivalent to a=a+2
  cout << a;
}