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c++/Others/Fig02_09.cpp - Test program for binary search.cpp

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+Fig02_09.cpp - Test program for binary search
+	
+	#include <iostream.h>
+        #include "vector.h"
+
+        const int NOT_FOUND = -1;
+
+/* START: Fig02_09.txt*/
+        /**
+         * Performs the standard binary search using two comparisons per level.
+         * Returns index where item is found or -1 if not found
+         */
+        template <class Comparable>
+        int binarySearch( const vector<Comparable> & a, const Comparable & x )
+        {
+/* 1*/      int low = 0, high = a.size( ) - 1;
+
+/* 2*/      while( low <= high )
+            {
+/* 3*/          int mid = ( low + high ) / 2;
+
+/* 4*/          if( a[ mid ] < x )
+/* 5*/              low = mid + 1;
+/* 6*/          else if( a[ mid ] > x )
+/* 7*/              high = mid - 1;
+                else
+/* 8*/              return mid;   // Found
+            }
+/* 9*/      return NOT_FOUND;     // NOT_FOUND is defined as -1
+        }
+/* END */
+
+        // Test program
+        int main( )
+        {
+            const int SIZE = 8;
+            vector<int> a( SIZE );
+
+            for( int i = 0; i < SIZE; i++ )
+                a[ i ] = i * 2;
+
+            for( int j = 0; j < SIZE * 2; j++ )
+                cout << "Found " << j << " at " << binarySearch( a, j ) << endl;
+            return 0;
+        }