蓝桥杯 算法提高 ADV-305 输出二进制表示

#include <iostream>
#include <cstdlib>

using namespace std;

char s[10];
int n;

int main()
{
    cin >> n;
    itoa(n, s, 2);

    int end = 0;
    while (s[end] != '\0')
        end++;
    end--;
    if (n >= 0) cout << 0;
    else cout << 1;

    int mask = 1, num = 0;
    for (int i = end; i >= 0 && i >= end - 6; i--) 
    {
        num += (s[i] - '0') * mask;
        mask *=  10;
    }
    printf("%07d", num);

    return 0;
}