#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void fun(int num);
int main(int argc, char *argv[])
{
	int num;
	printf("请输入一个数：");
	scanf("%d", &num);
	fun(num);
	putchar(10);

	return 0;
}

void fun(int num)
{
	if (num == 0)
	{
		return;
	}

	fun(num / 10);
	printf("%d ", num % 10);

}

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void fun(int num);
int main(int argc, char *argv[])
{

	int num;
	printf("请输入一个数：");
	scanf("%d", &num);
	fun(num);
	putchar(10);
	return 0;
}

void fun(int num)
{
	if (num == 0)
	{
		return;
	}

	printf("%d", num % 2);
	fun(num / 2);
}

#!/bin/bash

head -5 /etc/group | tail -1

mkdir /home/ubuntu/copy 

cd /home/ubuntu/copy

sudo cp /etc/shadow ./test

sudo chown root:ubuntu test

sudo chmod o-w,o-r,o-x test