Java Program to Generate Random Numbers Using Middle Square Method

This is java program to generate the random numbers. In mathematics, the middle-square method is a method of generating ‘pseudorandom’ numbers.To generate a sequence of 4-digit pseudorandom numbers, a 4-digit starting value is created and squared, producing an 8-digit number (if the result is less than 8 digits, leading zeroes are added to compensate). The middle 4 digits of the result would be the next number in the sequence, and returned as the result. This process is then repeated to generate more numbers.

Here is the source code of the Java Program to Generate Random Numbers Using Middle Square Method. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

//This is a sample program to generate random numbers using the middle square method
import java.util.Random;
import java.util.Scanner;
 
 
public class Middle_Suqare_Method 
{
    static int a[] = {1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000};
    static int middleSquareNumber(int numb, int dig)
    {
        int sqn = numb*numb, next_num=0;
        int trim = (dig/2);
        sqn = sqn / a[trim];
        for(int i=0; i<dig; i++)
        {
            next_num += (sqn%(a[trim]))*(a[i]);
            sqn = sqn/10;
        }
        return next_num;
    }
    public static void main(String args[])
    {
        System.out.println("Enter the #-digit random numbers you want: ");
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
 
        int start=1, end=1;
 
        start = a[n-1];
        end = a[n]; 
 
        Random rand = new Random();
        int number = rand.nextInt(end-start)+start;
        System.out.print("The random numbers are:\n" +number+", ");
        int new_number=0;
        for(int i=0; i<9; i++)
        {
            number = Middle_Suqare_Method.middleSquareNumber(number, n);
            System.out.print(number+", ");
        }
        System.out.print("...");
 
        sc.close();
    }
}

Output:

$ javac Middle_Square_Method.java
$ java Middle_Square_Method
Enter the #-digit random numbers you want: 
2
The random numbers are:
89, 92, 46, 11, 12, 14, 19, 36, 29, 84, ...