# C++ Program to Implement Park-Miller Random Number Generation Algorithm

This is a C++ Program to generate random numbers using Park-Miller algorithm. A general formula of a random number generator (RNG) of this type is:
X_{k+1} = g X(k) mod n
where the modulus n is a prime number or a power of a prime number, the multiplier g is an element of high multiplicative order modulo n (e.g., a primitive root modulo n), and the seed X0 is co-prime to n.

Here is source code of the C++ Program to Implement Park-Miller Random Number Generation Algorithm. The C++ program is successfully compiled and run on a Linux system. The program output is also shown below.

1. #include <iostream>
2. #include <math.h>
3. #include <stdlib.h>
4.
5. using namespace std;
6.
7. const long m = 2147483647L;
8. const long a = 48271L;
9. const long q = 44488L;
10. const long r = 3399L;
11.
12. static long r_seed = 12345678L;
13.
14. double uniform()
15. {
16.     long hi = r_seed / q;
17.     long lo = r_seed - q * hi;
18.     long t = a * lo - r * hi;
19.     if (t > 0)
20.         r_seed = t;
21.     else
22.         r_seed = t + m;
23.     return r_seed;
24. }
25.
26. int main(int argc, char **argv)
27. {
28.     double A[10];
29.
30.     for (int i = 0; i < 10; i++)
31.         A[i] = uniform();
32.
33.     cout<<"Random numbers are:\n";
34.     for (int i = 0; i < 10; i++)
35.         cout << A[i]<<endl;
36. }

Output:

\$ g++ ParkMillerRandomNumbers.cpp
\$ a.out

Random numbers are:
1.08525e+009
5.0826e+008
1.35229e+009
1.56324e+009
8.90733e+008
1.81003e+009
1.50959e+009
8.62973e+008
1.85299e+009
6.77684e+008

Sanfoundry Global Education & Learning Series – 1000 C++ Programs.