Vector

#include <iostream>

using namespace std;

class Vector
{
    int size;
    double * values;
public:
    Vector(int n, double d = 0);
    Vector(const Vector & v);
    ~Vector();

    int getSize() const {return size;};
    double & getVal(int) const;

    double & operator[](int index) const {return getVal(index);};
    Vector & operator=(const Vector &);

    void show() const;
    bool isEmpty() const {return (size==0);};

    void fill(const double & d){for(int i=0; i<size; values[i++]=d);};
    void zeros(){fill(0);};
    void ones(){fill(1);};

    friend Vector operator-(const Vector &);

    friend Vector operator-(const Vector &, const Vector &);
    friend Vector operator-(const Vector &, const double &);
    friend Vector operator-(const double &, const Vector &);

    friend Vector operator+(const Vector &, const Vector &);
    friend Vector operator+(const Vector &, const double &);
    friend Vector operator+(const double &, const Vector &);
};

int main()
{
    Vector a(3, 1), b(3, -1);
    for(int i=1; i<a.getSize(); ++i) a[i]=a[i-1]+1;
    for(int i=1; i<b.getSize(); ++i) b[i]=b[i-1]-1;
    cout << "Vector a = "; a.show();
    cout << "Vector b = "; b.show();
    Vector c = a + b;
    cout << "Vector c = a + b = "; c.show();
    double d = 5;

    c = a + d;
    cout << "Vector c = a + " << d << " = "; c.show();

    c = d + a;
    cout << "Vector c = " << d << " + a = "; c.show();

    c = b - a;
    cout << "Vector c = b - a = "; c.show();

    c = b - d;
    cout << "Vector c = b - " << d << " = "; c.show();

    c = d - b;
    cout << "Vector c = " << d << " - b = "; c.show();
}

Vector operator-(const Vector & v)
{
    Vector temp = v;
    for(int i=0; i < temp.size; ++i)
        temp[i]= -temp[i];
    return temp;
}

Vector operator-(const Vector & a, const Vector & b)
{
    return a + (-b);
}

Vector operator-(const Vector & a, const double & d)
{
    return a + (-d);
}

Vector operator-(const double & d, const Vector & a)
{
    return d + (-a);
}

Vector operator+(const Vector & a, const Vector & b)
{
    bool aMax = a.size > b.size;
    int maxSize = aMax ? a.size:b.size;
    int minSize = aMax ? b.size:a.size;
    Vector temp(maxSize);
    for(int i = 0; i < minSize; ++i)
        temp[i] = a[i] + b[i];
    for(int i = minSize; i < maxSize; temp[i++] = aMax ? a[i]:b[i]);
    return temp;
}

Vector operator+(const Vector & v, const double & d)
{
    Vector temp(v);
    if (!temp.isEmpty())
        temp[0] += d;
    return temp;
}

Vector operator+(const double & d, const Vector & v)
{
    Vector temp(v);
    if (!temp.isEmpty())
        temp[temp.size-1] += d;
    return temp;
}

void Vector::show() const
{
    for (int i = 0; i < size; ++i)
        cout << values[i] << " ";
    cout << endl;
}

double & Vector::getVal(int index) const
{
    if (index < 0) index = 0;
    if (index >= size) index = size-1;
    return values[index];
}

Vector & Vector::operator=(const Vector & v)
{
    delete[] values;
    size = v.size;
    values = new double[size];
    for(int i = 0; i < size; ++i)
        values[i] = v.values[i];
    return *this;
}

Vector::Vector(int n, double d)
{
    size = n;
    values = new double[size];
    fill(d);
}

Vector::Vector(const Vector & v)
{
    size = v.size;
    values = new double[size];
    for(int i = 0; i < size; ++i)
        values[i] = v.values[i];
}

Vector::~Vector()
{
    delete[] values;
}