你好，随机数有规律吗？毕竟程序也是人制造出来的！

没有规律，所以才叫做随机。

但从概率上说，是有规律的。比如说从1-10选1个数，出现哪一个都有可能，所以叫随机。但选1万次的话，应该每个数都出现数百至一千多次，而不会说1万次都是5.

#include <iostream>

void print(int *arr, int length) {

for (int i = 0i <length++i) {

std::cout <<*(arr + i)

}

std::cout <<std::endl

}

void swap(int *arr1, int *arr2) {

int temp = *arr1

*arr1 = *arr2

*arr2 = temp

}

void permutate(int *arr, int length, int *subArr, int subLen) {

if (subLen == 1) { print(arr, length)}

else {

for (int i = 0i <subLen++i) {

swap(subArr, subArr + i)

permutate(arr, length, subArr + 1, subLen - 1)

swap(subArr, subArr + i)

}

}

}

void permutate(int *arr, int length) {

permutate(arr, length, arr, length)

}

int main()

{

int n

std::cout <<"enter a number n: (1 <= n <= 9)" <<std::endl

std::cin >>n

int *arr = new int[n]

for (int i = 0i <n++i) {

arr[i] = i + 1

}

permutate(arr, n)

delete [] arr

return 0

}

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