#include <iostream>
#include <cmath>

using namespace std;

struct vect
{
    double x,y;
};

void add(vect &a, vect &b);
void subtract(vect &a, vect &b);
void multiply(vect &a, vect &b);
void scalarProduct(vect &a, vect &b);
void magnitude(vect &a, vect &b);

int main()
{
    int o;
    vect a, b;

    cout << "Please enter the x value for the first vector: ";
    cin >> a.x;
    cout << "Please enter the y value for the first vector: ";
    cin >> a.y;
    cout << "Please enter the x value for the second vector: ";
    cin >> b.x;
    cout << "Please enter the y value for the second vector: ";
    cin >> b.y;

    do
    {
        cout << "What would you like to do:\n1. Add\n2. Subtract\n3. Multiply\n4. Find the scalar product\n5. Find the magnitude\n";
        cin >> o;

        switch(o)
        {
            case 1: add(a,b);
            break;
            case 2: subtract(a,b);
            break;
            case 3: multiply(a,b);
            break;
            case 4: scalarProduct(a,b);
            break;
            case 5: magnitude(a,b);
            break;
        }
    }
    while( o <= 5 && o >= 1 );

    return 0;
}

void add(vect &a, vect &b)
{
    cout << "(" << a.x + b.x << "," << a.y + b.y << ")" << endl;
}

void subtract(vect &a, vect &b)
{
    cout << "(" << a.x - b.x << "," << a.y - b.y << ")" << endl;
}

void multiply(vect &a, vect &b)
{
    cout << "(" << a.x * b.x << "," << a.y * b.y << ")" << endl;
}

void scalarProduct(vect &a, vect &b)
{
    cout << (a.x * b.x) + (a.y * b.y) << endl;
}

void magnitude(vect &a, vect &b)
{
    int i;
    cout << "Which vector would you like to know the magnitude of?\n1: (" << a.x << "," << a.y << ")\n2: (" << b.x << "," << b.y << ")\n";
    cin >> i;

    switch(i)
    {
        case 1: cout << sqrt((a.x*a.x) + (a.y*a.y)) << " or √" << (a.x*a.x) + (a.y*a.y) << endl;
        break;
        case 2: cout << sqrt((b.x*b.x) + (b.y*b.y)) << " or √" << (b.x*b.x) + (b.y*b.y) << endl;
        break;
    }
}