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

Park-Miller Random Number Generation Algorithm is another method of generating random numbers.

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, and the seed X0 is coprime to n.

## Algorithm

Begin
Declare variables n, a, b, c and seed
Read variables n, a, b, c and seed
Uniform()
Declare variable hi, lo, t
hi=seed divided by b
lo = seed - b * hi
t = a * lo - c * hi
if (t > 0)
seed = t;
else
seed = t + n;
return seed;
Done
For i =0 to n
Call the function random
Done
End

## Example Code

#include <iostream>
using namespace std;
const long n = 2145678965L;
const long a = 763214L;
const long b = 88844L;
const long c = 7766L; i
static long seed = 12345678L;
double uniform() {
long hi = seed / b;
long lo = seed - b * hi;
long t = a * lo - c * hi;
if (t > 0)
seed = t;
else
seed = t + n;
return seed;
}
int main(int argc, char **argv) {
double A[10];
for (int i = 0; i < 10; i++)
A[i] = uniform();
cout << "Random numbers are:\n";
for (int i = 0; i < 10; i++)
cout << A[i] << endl;
}

## Output

Random numbers are:
6.50293e+10
4.27187e+10
2.1539e+10
4.62058e+10
1.70792e+10
8.24569e+09
5.93381e+10
3.63839e+10
4.81931e+10
8.91007e+09

Updated on: 30-Jul-2019

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