분명 맞는거같은데 왜이럴까요..?  

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<iostream>
using namespace std;;
int _pow(int x, int e) {
	if (e == 0)
		return 1;
	return x * _pow(x, e - 1);
}
void convert_prt(int _x) {
	int x = _x;
	int sum = 0;
	int i = 0;
	while (x != 0) {
		int n = x % 10;
		sum += n * _pow(8, i++);
		x /= 10;
	}
	x = sum;
	int k = 1 << 30;
	bool isStart = false;
	while (k != 0) {
		if ((k&x) != 0) {
			isStart = true;
			printf("1");
		}
		else if (isStart) {
			printf("0");
		}
		k = k >> 1;
	}
	return;
}
int main()
{
	int oct;
	scanf("%d",&oct);
	if (oct == 0) {
		printf("0");
	}
		
	convert_prt(oct);
	return 0;
}