Program to find the greatest number using pointers

#include<stdio.h>

void main()

{

    int a[20],i,*p,x,*y,n;

    printf("How many numbers?");

    scanf("%d",&n);

    p=a;

    y=&x;

    printf("Enter %d numbers:",n);

    for(i=0;i<n;i++)

    {

        scanf("%d",(p+i));

    }

    *y=*p;

    for(i=0;i<n;i++)

    {

        if(*y<*(p+i))

        *y=*(p+i);

    }

    printf("\n The greatest number is %d.",x);

}