C语言中printf直接打出2进制数是%什么?16进制是什么？

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
using namespace std;


char * get2String(long num)
{
int i = 0;
char * buffer = NULL;
char * temp = NULL;
printf("%d\n", num);


buffer = (char *)malloc(33);
temp = buffer;


for(i=0; i<32; i++)              
{
//temp[i] = num & (1 << (31 - i));

//temp[i] = temp[i] >> (31 - i);//(因为定义为char型所以每个数组成员最大为255如果分步移位会造成第一步移位后数据溢出)

temp[i] =(num&(1<<(31-i)))>>(31-i);

temp[i] = (temp[i] == 0) ? '0' : '1';
}
buffer[32] = '\0';


return buffer;
}
char * get16String(long num)
{
int i = 0;
char * buffer = (char *)malloc(11);
char * temp;


buffer[0] = '0';
buffer[1] = 'x';
buffer[10] = '\0';
temp = buffer+2;


for(i=0; i<8; i++)
{
temp[i] = (char)( (num << (4 * i)) >> 28);
temp[i] = temp[i] >= 0 ? temp[i] : temp[i] + 16;
temp[i] = temp[i] < 10 ? temp[i] + 48 : temp[i] + 55;
}
return buffer;
}


int main()
{
char *p = NULL;
char *q = NULL;
int num = 0;
int a = -9;
printf("%d\n", a>>1);


printf("input num: ");
scanf("%d", &num);


p = get16String(num);
q = get2String(num);



printf("%s\n", p);
printf("%s\n", q);


return 0;
}