**fig2_9.txt**

/* 1*/	// Return position of X in A.

/* 2*/	int
/* 3*/	Binary_Search( const Etype A[ ], const Etype & X, const int N )
/* 4*/	{
/* 5*/	    int Low = 0, High = N - 1;
/* 6*/	    int Mid;

/* 7*/	    while( Low <= High )
/* 8*/	    {
/* 9*/	        Mid = ( Low + High ) / 2;
/*10*/	        if( A[ Mid ] < X )
/*11*/	            Low = Mid + 1;
/*12*/	        else if( A[ Mid ] > X )
/*13*/	            High = Mid - 1;
/*14*/	        else
/*15*/	            return Mid;
/*16*/	    }

/*17*/	    return Not_Found;		// Return -1.
/*18*/	}