Simpson's 3/8th rule to find Integration of Difference Table

#include<iostream>
using namespace std;
int main()
{
    int i,n;
    float x[10],y[10],h,sum;

    cout<<"Enter no of values in table: ";
    cin>>n;
    cout<<"Enter X & corresponding Y:\n";
    for(i=0;i<n;i++)
        cin>>x[i]>>y[i];

    h=x[1]-x[0];
    sum=y[0]+y[n-1];
    for(i=1;i<n-1;i++)
    {
        if(i%3==0)
            sum+=2*y[i];
        else
            sum+=3*y[i];
    }
    cout<<"Integral vlaue="<<(3*(h/8))*sum;
    return 0;
}