2的大數

#include "stdio.h"
int main()
{
	int n;
	int a[3015] = { 0 }, howlong = 0;
	while (scanf("%d", &n) != EOF)
	{
		for (int i = 0; i < 3015; i++)//將每位元預設為0
		{
			a[i] = 0;
		}
		howlong = 0;
		a[0] = 1;
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < 3015; j++)//將每位元*2
			{
				a[j] *= 2;
			}
			for (int j = 0; j < 3015; j++)
			{
				if (a[j] >= 10)
				{
					a[j] -= 10;//過10-10
					a[j + 1]++;//下一位進1
					howlong = j + 1;//紀錄長度
				}
			}
		}
		int i = howlong;
		while (i >= 0)
		{
			printf("%d", a[i]);
			i--;
		}
		printf("\n");
	}
	return 0;
}