Question

We all know && (double and) for and condition.
for single and What happen internally how condition gets executed.

 if(true & bSuccess)
{
}

Answer 1

true & bSuccess

in this expression both operands are promoted to int and then & is evaluated. If bSuccess is true you will get 1 & 1 which is 1 (or true). If bSuccess is false you’ll get 1 & 0 which is 0 (or false)

So, in case of boolean values && and & will always yield the same result, but they are not totally equivalent in that & will always evaluate both its arguments and && will not evaluate its second argument if the first one is false.

Example:

bool f() { std::cout << "f"; return false; }
bool g() { std::cout << "g"; return true; }

int main()
{
    f() && g(); //prints f. Yields false
    f() & g();  //prints fg or gf (unspecified). Yields 0 (false)
}