操作符的重载以及数组/vector对象的初始化

>> cat operator.C
#include <iostream>
#include <vector>
using namespace std;

class A
{
public:
A(int i = 0):a(i)
{
cout << " I am in A() " << endl;
}
A(const A &x)
{
cout << " I am in A(const A&) " << endl;
a=x.a;
}
A& operator=(int i)
{
cout << " I am in operator() " << endl;
a=i;
return *this;
}
operator int()
{
cout << " I am in operator int() " << endl;
return a;
}
private:
int a;
};

int main()
{
A a =3;

a=4;

int x = a;
cout << x << endl;

cout << "test array of A " << endl;
A a1[10];

cout << "test vector of A " << endl;
vector<A> v(10);
}

>> ./a.out
I am in A()
I am in operator()
I am in operator int()
4
test array of A
I am in A()
I am in A()
I am in A()
I am in A()
I am in A()
I am in A()
I am in A()
I am in A()
I am in A()
I am in A()
test vector of A
I am in A()
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)
I am in A(const A&)