one-file-projects/vectors.cpp

#include <iostream>

template<unsigned int NDim, typename TElem>
class Vector {
private:
    TElem coord[NDim];
public:
    Vector() {}

    Vector(const TElem initial) {
        for(unsigned int i = 0; i < NDim; i++) {
            coord[i] = initial;
        }
    }

    Vector<NDim, TElem>
    operator+ (const Vector<NDim, TElem>& other)
    {
        Vector<NDim, TElem> result;
        for(unsigned int i = 0; i < NDim; i++) {
            result[i] = this->coord[i] + other[i];
        }
        return result;
    }

    Vector<NDim, TElem>
    operator+= (const Vector<NDim, TElem>& other)
    {
        for(unsigned int i = 0; i < NDim; i++) {
            this->coord[i] += other[i];
        }
        return *this;
    }

    Vector<NDim, TElem>
    operator- ()
    {
        Vector<NDim, TElem> result;
        for(unsigned int i = 0; i < NDim; i++)
        {
            result[i] = -this->coord[i];
        }
        return result;
    }

    Vector<NDim, TElem>
    operator*(TElem factor)
    {
        Vector<NDim, TElem> result;
        for(unsigned int i = 0; i < NDim; i++) {
            result[i] = this->coord[i] * factor;
        }
        return result;
    }

    TElem& operator[](const unsigned int index) {
        return this->coord[index];
    }

    const TElem operator[](const unsigned int index) const {
        return this->coord[index];
    }
};

template<unsigned int NDim>
void printVector(const Vector<NDim, int> v) {
    printf("%d", v[0]);
    for(int i = 1; i < NDim; i++) {
        printf(", %3d", v[i]);
    }
    printf("\n");
}

#define DIM 3

int main( int argc, char *argv[] ) {
    Vector<DIM,int> a(0),b(0),c(0),d(0);
    for(int i = 0; i < DIM; i++) {
        a[i] = 10*i;
        b[i] = 5-i;
    }

    printVector(a);
    printVector(b);

    c = a + b;

    printVector(c);

    d = a*3 + c*4;

    printVector(d);

	return 0;
}