Constructors are not inherited. They are called implicitly or explicitly by the child constructor.
The compiler creates a default constructor (one with no arguments) and a default copy constructor (one with an argument which is a reference to the same type). But if you want a constructor that will accept an int, you have to define it explicitly.
class A
{
public:
explicit A(int x) {}
};
class B: public A
{
public:
explicit B(int x) : A(x) { }
};
UPDATE: In C++11, constructors can be inherited. See Suma's answer for details.