下面给大家两段代码

1st

#include <bits/stdc++.h>
#define int long long
using namespace std;
int s(int a) {
	int sum = 0;
	while (a) {
		sum += a % 10;
		a /= 10;
	}
	return sum;
}
signed main()
{
	int n;
	int x;
	cin >> n;
	while (n --) {
		cin >> x;
		int t = s(x);
		if(t % 7 == 0)
			cout << "Yes\n";
		else
			cout << "No\n";
	}
    return 0;
}

2nd

#include <bits/stdc++.h>
#define int long long
using namespace std;
int s(int a) {
	int sum = 0;
	while (a) {
		sum += a % 10;
		a /= 10;
	}
	return sum;
}
signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	int n;
	int x;
	cin >> n;
	while (n --) {
		cin >> x;
		int t = s(x);
		if(t % 7 == 0)
			cout << "Yes\n";
		else
			cout << "No\n";
	}
    return 0;
}

可见，上面两段代码除了io方式，其他都一样，但是（样例这里取）输出却不一样，这是为什么？