将十进制转换成二进制输出，递归写法

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

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

int a = 30;
binary_num(a, sizeof(a) * 8);

printf("\n");
system("pause");
return 0;
}

void binary_num(int a, int i)
{
if (i > 1)
binary_num(a >> 1, --i );
if (a & 1)
printf("1");
else
printf("0");
}