#include <iostream>
#include <cstdio>
#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n,a;
    cin>>n;
    for(int i=1;i<=n;i++)
        {
            int ans=0;
            cin>>a;
            while(a)
                {
                    ans+=a%10;
                    a/=10;
                }
            if(ans%7==0)
            {
                cout<<"Yes"<<endl;
            }
            else
            {
                cout<<"No"<<endl;
            }
        }
    return 0;
}

老样子，自定义函数启动

#include <iostream>
using namespace std;
int a[1000];
bool number(int n)
{
	int sum=0;
	while (n!=0)
	{
		sum+=n%10;
		n/=10;
	}
	if(sum%7==0) return 1;
	else return 0;
}
int main()
{
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		if(number(a[i]))
		{
			cout<<"Yes"<<endl;
		}
		else cout<<"No"<<endl;
	}
return 0;
}