memory leak problem

[bingo]

Hi, All:
I'm really new to C++, so please forgive If I asked stupid
questions:

I was trying to use the following Vector class to do some
calculations:

=============================
class Vector {
public:
double x,y,z;

inline Vector(void) : x(-99999), y(-99999), z(-99999) { ; }
// inline Vector(void) { ; }

inline Vector( double newx, double newy, double newz)
: x(newx), y(newy), z(newz) { ; }

inline Vector( double newv ) // allow Vector v = 0; etc.
: x(newv), y(newv), z(newv) { ; }

inline Vector(const FloatVector &v) : x(v.x), y(v.y), z(v.z)
{ ; }

inline double operator[](int i) {
return i==0 ? x
:i==1 ? y
:i==2 ? z
: x;

}

// v1 = v2
inline Vector& operator=(const Vector &v2) {
x = v2.x;
y = v2.y;
z = v2.z;
return *this;
}

// v1 = const;
inline Vector& operator=(const double &v2) {
x = v2;
y = v2;
z = v2;
return *this;
}

// addition of two vectors
inline friend Vector operator+(const Vector& v1, const Vector&
v2) {
return Vector( v1.x+v2.x, v1.y+v2.y, v1.z+v2.z);
}

// negation
inline friend Vector operator-(const Vector &v1) {
return Vector( -v1.x, -v1.y, -v1.z);
}

// subtraction
inline friend Vector operator-(const Vector &v1, const Vector
&v2) {
return Vector( v1.x-v2.x, v1.y-v2.y, v1.z-v2.z);
}

// inner ("dot") product
inline friend double operator*(const Vector &v1, const Vector
&v2) {
return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
}
// scalar product
inline friend Vector operator*(const double &f, const Vector &v1)
{
return Vector(f*v1.x, f*v1.y, f*v1.z);
}
// scalar product
inline friend Vector operator*(const Vector &v1, const double &f)
{
return Vector(f*v1.x, f*v1.y, f*v1.z);
}
// division by a scalar
inline friend Vector operator/(const Vector &v1, const double &f)
{
return Vector(v1.x/f, v1.y/f, v1.z/f);
}

};
=======================================

and my main program looks like this:

int main () {

Vector a, b, c, d;
a = b - c + d;
a = b * 0.5;
......
}

Now my question is : for the operation - , + and scalar product, will
it create a new Vector for return, and not be released in my
calculation, which finally leads to memory leak? If so, how can I
solve the problem?

Thanks a lot.
-Bin