例1 编写一个函数getbits，实现从一个16位的单元中取出某几位

#include <iostream>
using namespace std;


unsigned getbits(unsigned value, int n1, int n2);


int main()
{
unsigned a;
int n1, n2;
printf("请输入一个八进制数a: ");
scanf("%o",&a);
printf("%d\n",a);
printf("请输入起始位n1，结束位n2：");
scanf("%d,%d",&n1,&n2);
printf("%o\n",getbits(a,n1-1,n2));
system("pause");
return 0;
}


unsigned getbits(unsigned value, int n1, int n2)
{
unsigned z;
z=~0;
<