Searching an element using Binary Search

Problem Statement
Write a C program to search a element in an array using Binary Search method

#include<stdio.h>
int main()
{
  int n,i,search,f=0,low,high,mid,a[20];
  printf("Enter the n value:");
  scanf("%d",&n);
  for(i=1;i<=n;i++)
    {
      printf("Enter the number in ascending order a[%d]=",i);
      scanf("%d",&a[i]);
    }
  printf("Enter the search element:");
  scanf("%d",&search);
  low=1;
  high=n;
  while(low<=high)
    {
      mid=(low+high)/2;
      if(search<a[mid])
    {
      high=mid-1;
    }
      else if(search>a[mid])
    {
      low=mid+1;
    }
      else
    {
      f=1;
      printf("obtainedin the position %d: \n",mid);
      break;
    }
    }
  if(f==0)
    {
      printf("not present");
    }
  return 0;
}