二分法

#include<stdio.h>
int b[10]={1,3,5,6,8,9,13,14},a
int erfen (int x,int y)
{
int o;
if(x>y)
return 0;
else
{
o=(x+y)/2;
if(b[o]==a)
return 0;
if(a<b[o])
return erfen(x,o-1);
else return erfen(o+1,y);
}
return -1;
}
int main()
{
int n,x=0,y=0;
scanf("%d",&n)
printf("%d",erfen(x,y));
return 0;


}