Binary search in a sorted array

/* Binary search in a sorted array. */

#include <stdio.h>
#include <conio.h>

void main( )
{
int arr[10] = { 1, 2, 3, 9, 11, 13, 17, 25, 57, 90 } ;
int mid, lower = 0 , upper = 9, num, flag = 1 ;

clrscr( ) ;

printf ( "Enter number to search: " ) ;
scanf ( "%d", &num ) ;

for ( mid = ( lower + upper ) / 2 ; lower <= upper ;
mid = ( lower + upper ) / 2 )
{
if ( arr[mid] == num )
{
printf ( "The number is at position %d in the array.", mid ) ;
flag = 0 ;
break ;
}
if ( arr[mid] > num )
upper = mid - 1 ;
else
lower = mid + 1 ;
}

if ( flag )
printf ( "Element is not present in the array." ) ;

getch( ) ;
}