added the project files

projects/randomNumberGeneratorExamples/PRNG.h

@@ -0,0 +1,51 @@
+// Pseudo Random Number Generator : generate repeatable sequence of values that
+//   appear random by scrambling the bits of a 32-bit integer value.
+//
+// Interface :
+//   PRNG(s) - set starting seed 
+//   seed() - read seed
+//   seed(s) - reset seed
+//   prng() - generate random value in range [0,UINT_MAX]
+//   prng(u) - generate random value in range [0,u]
+//   prng(l,u) - generate random value in range [l,u]
+//
+// Examples : generate random number between 5-21
+//   prng() % 17 + 5	values 0-16 + 5 = 5-21
+//   prng( 16 ) + 5
+//   prng( 5, 21 )
+
+#ifndef __PRNG_H__
+#define __PRNG_H__
+
+#include <cstdint>					// uint32_t
+#include <cassert>					// assert
+
+class PRNG {
+    uint32_t  seed_;	// same results on 32/64-bit architectures
+  public:
+    PRNG( uint32_t  s = 362436069 ) {			// default seed
+	seed_ = s;					// set seed
+	assert( ((void)"invalid seed", seed_ != 0) );
+    }
+    uint32_t seed() {					// read seed
+	return seed_;
+    }
+    void seed( uint32_t  s ) {				// reset seed
+	seed_ = s;					// set seed
+	assert( ((void)"invalid seed", seed_ != 0) );
+    }
+    uint32_t operator()() {				// [0,UINT_MAX]
+	seed_ = 36969 * (seed_ & 65535) + (seed_ >> 16); // scramble bits
+	return seed_;
+    }
+    uint32_t operator()( uint32_t u ) {			// [0,u]
+	assert( ((void)"invalid random range", u < (uint32_t)-1) );
+	return operator()() % (u + 1);			// call operator()()
+    }
+    uint32_t operator()( uint32_t l, uint32_t u ) {	// [l,u]
+	assert( ((void)"invalid random range", l <= u) );
+	return operator()( u - l ) + l;			// call operator()( uint32_t )
+    }
+};
+
+#endif