#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
void swap(char *p1, char *p2)
{
char tmp = *p1;
*p1 = *p2;
*p2 = tmp;
}
void reverse(char *pstart, char *pend)
{
assert((pstart != NULL) && (pend != NULL));
while (pstart < pend)
{
swap(pstart, pend);
pstart++;
pend--;
}
}
char *my_itob(int n, char s[], int b)
{
char *p = s;
assert(s != NULL);
if (s != NULL)
{
if (n < 0)
{
*s == '-';
n = n*(-1);
s++;
}
while (n)
{
*s = "0123456789abcdef"[n%b];
n /= b;
s++;
}
*s = '\0';
if (*p == '-')
reverse(p + 1, (p + strlen(p) - 1));
else
reverse(p, (p + strlen(p) - 1));
return p;
}
return NULL;
}
int main()
{
int num = 0;
scanf("%d", &num);
char output[20];
char *p = my_itob(num, output, 2);
printf("%s\n", p);
system("pause");
return 0;
}
