#include <stdio.h>

void f (int Y[10] , int x) {
    int j, k;
    int i= 0; j = 9;
    do {
        k = (i+ j) / 2;
        if( Y[k] < x) 
        	i = k;
        else 
        	j = k;
    } while ((Y[k] != x) && (i < j));
    if(Y[k] == x) 
    	printf(" x is in the array ");
    else 
    	printf(" x is not in the array ");
}

int main(void) {
	int *Y;
	int B[]={1,3,5,7,9,11,13,15,17,19};
	Y = B;
	f(Y,0);
	return 0;
}