 # 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 << "..."; } ``` 