Initial commit

c++/Others/Random.cpp - Implementation for random number class.cpp

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+Random.cpp - Implementation for random number class
+	
+	#include "Random.h"
+
+
+        static const int A = 48271;
+        static const int M = 2147483647;
+        static const int Q = M / A;
+        static const int R = M % A;
+
+        /**
+         * Construct with initialValue for the state.
+         */
+        Random::Random( int initialValue )
+        {
+            if( initialValue < 0 )
+                initialValue += M;
+
+            state = initialValue;
+            if( state == 0 )
+                state = 1;
+        }
+
+        /**
+         * Return a pseudorandom int, and change the
+         * internal state.
+         */
+        int Random::randomInt( )
+        {
+            int tmpState = A * ( state % Q ) - R * ( state / Q );
+            if( tmpState >= 0 )
+                state = tmpState;
+            else
+                state = tmpState + M;
+
+            return state;
+        }
+
+        /**
+         * Return a pseudorandom int, and change the
+         * internal state. DOES NOT WORK.
+         */
+        int Random::randomIntWRONG( )
+        {
+            return state = ( A * state ) % M;
+        }
+
+        /**
+         * Return a pseudorandom double in the open range 0..1
+         * and change the internal state.
+         */
+        double Random::random0_1( )
+        {
+            return (double) randomInt( ) / M;
+        }
+
+        /**
+         * Return an int in the closed range [low,high], and
+         * change the internal state.
+         */
+        int Random::randomInt( int low, int high )
+        {
+            double partitionSize = (double) M / ( high - low + 1 );
+
+            return (int) ( randomInt( ) / partitionSize ) + low;
+        }