#include<myhead.h>void fun(int n)
{if(n>9){fun(n/10);printf("%d\t",n%10);putchar(10);return;}else{printf("%d\n",n%10);return;}
}
int main(int argc, const char *argv[])
{int num;printf("请输入一个整数：");scanf("%d",&num);fun(num);return 0;
} 
#include<myhead.h>void fun(int n)
{if(n>0){fun(n/2);printf("%d",n%2);}
}
int main(int argc, const char *argv[])
{int num;printf("请输入一个数：");scanf("%d",&num);fun(num);putchar(10);return 0;
} 
#!/bin/bash
head -5 /etc/group | tail -1
mkdir /home/ubuntu/copy
cd /home/ubuntu/copy
sudo cp /etc/shadow /home/ubuntu//copy/test
sudo chown root /home/ubuntu//copy/test
sudo chmod o-w,o-r,o-x /home/ubuntu//copy/test
ubuntu@ubuntu:~/23051/C高级/day2$
)