Class Template for vector operations.

#include <iostream.h>
#include <conio.h>

template <class T>
class vector
{
    T *arr;
    int size;

    public:

    vector() {
       arr=NULL;
       size=0;
    }

    vector(int m);
    vector(T *a,int n);
    void modify(T value,int index);
    void multiply(int scalarvalue);
    void display();
};

template <class T>
vector<T> :: vector(int m)
{
   size=m;
   arr = new T[size];
   for(int i=0;i<size;i++)
       arr[i]=0;
}

template <class T>
vector<T> :: vector(T *a,int n)
{
   size=n;
   arr = new T[size];
   for(int i=0;i<size;i++)
       arr[i]=a[i];
}


template <class T>
void vector<T> :: modify(T value,int index)
{
    arr[index]=value;
}


template <class T>
void vector<T> :: multiply(int scalarvalue)
{
    for(int i=0;i<size;i++)
       arr[i] = arr[i] * scalarvalue;
}

template <class T>
void vector<T> :: display()
{
    cout<<"(";
    for(int i=0;i<size;i++)
    {
        cout<<arr[i];
        if(i!=size-1)
           cout<<", ";
    }
    cout<<")";
}


void main()
{
    clrscr();


    //Creating Integer Vector.
    int iarr[]={1,2,3,4,5};
    vector <int> v1(iarr,5); //Integer array with 5 elements.
    cout<<"\nInteger Vector : ";
    v1.display();
    cout<<"\n\nModify index 3 with value 15\n";
    v1.modify(15,3); //modifying index 3 with value 15.
    cout<<"After Modification : ";
    v1.display();
    cout<<"\n\nMultiply with scalar value : 10\n";
    v1.multiply(10); //Multiply with scalar value 10.
    cout<<"After Multiplying : ";
    v1.display();
    cout<<"\n\n";


    //Creating double Vector.
    double darr[]={1.1,2.2,3.3,4.4,5.5};
    vector <double> v2(darr,5); //Double array with 5 elements.
    cout<<"\nDouble Vector : ";
    v2.display();
    cout<<"\n\nModify index 0 with value 9.9 \n";
    v2.modify(9.9,0); //modifying index 0 with value 9.9.
    cout<<"After Modification : ";
    v2.display();
    cout<<"\n\nMultiply with scalar value : 10\n";
    v2.multiply(10); //Multiply with scalar value 10.
    cout<<"After Multiplying : ";
    v2.display();
    cout<<"\n\n";

    getch();

}