Simpson's 1/3 Method in C

#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
  float x[10],y[10],sum=0,h,temp;
  int i,n,j,k=0;
  float fact(int);
  clrscr();
  printf("\nhow many record you will be enter: ");
  scanf("%d",&n);
  for(i=0; i<n; i++)
  {
   printf("\n\nenter the value of x%d: ",i);
   scanf("%f",&x[i]);
   printf("\n\nenter the value of f(x%d): ",i);
   scanf("%f",&y[i]);
  }
  h=x[1]-x[0];
  n=n-1;
  sum = sum + y[0];
  for(i=1;i<n;i++)
  {
    if(k==0)
    {
     sum = sum + 4 * y[i];
     k=1;
    }
    else    {
     sum = sum + 2 * y[i];
     k=0;
    }
   }
   sum = sum + y[i];
   sum = sum * (h/3);
   printf("\n\n  I = %f  ",sum);
getch();
}




-------------------------- OUTPUT ----------------------


how many record you will be enter: 5


enter the value of x0: 0


enter the value of f(x0): 1


enter the value of x1: 0.25


enter the value of f(x1): 0.8


enter the value of x2: 0.5


enter the value of f(x2): 0.6667


enter the value of x3: 0.75


enter the value of f(x3): 0.5714


enter the value of x4: 1


enter the value of f(x4): 0.5


       I = 0.693250