整形转二进制思路：
void tobin(unsigned long n);
int main(void)
{
unsigned long n = 0;
printf_s("输入你需要转换的二进制数\n");
while ((scanf_s("%lu", &n)) == 1)
{
tobin(n);
printf_s("输入q结束;\n");
}
}
void tobin(unsigned long n)
{
int r;
r = n % 2;
printf_s("r = %d\n", r);
if (n >= 2)
{
tobin(n / 2);
}
printf_s("%c>>",r == 0 ? '0' : '1');
return;
}
