C++ Programming Code Examples
C++ > Mathematics Code Examples
Generate Random Numbers Using Middle Square Method
/* Generate Random Numbers Using Middle Square Method
This is a C++ Program to generate random numbers using Middle Square method. In mathematics, the middle-square method is a method of generating pseudorandom numbers. In practice it is not a good method, since its period is usually very short and it has some severe weaknesses, such as the output sequence almost always converging to zero. */
#include <iostream>
#include <math.h>
#include <stdlib.h>
using namespace std;
int a[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000 };
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;
}
int main(int argc, char **argv)
{
cout << "Enter the #-digit random numbers you want: ";
int n;
cin >> n;
int start = 1, end = 1;
start = a[n - 1];
end = a[n];
int number = ((rand()) % (end - start)) + start;
cout << "The random numbers are:\n" << number << ", ";
for (int i = 1; i < n; i++)
{
number = middleSquareNumber(number, n);
cout << number << ", ";
}
cout << "...";
}
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