[Excel] the difference between text and numeric values

excel tend to be directly entered when the value of the digital input, but we sometimes enter the phone number will be treated as numerical processing, causing unnecessary trouble. Today we look at how digital input text.
When the input digital text, you need to enter a prefix single quotation marks before the text '123, and then enter the text you can handle

In the upper left corner there will be a green triangle logo, which is a digital text. While a value of the cell without such identification.

#include<iostream>
using namespace std;
int s1,s2,s3;
bool flag = 1;
int main()
{
    freopen("1.txt","r",stdin);
    freopen("2.txt","w",stdout);
    int k;cin >> k;
    for(int i = 10000;i <= 30000;i++)
    {
        s1 = i / 100;
        s3 = i % 1000;
        s2 = (i/10)%1000;
        if(s1%k==0&&s2%k==0&&s3%k==0)
            {
                cout << i <<endl;
                flag = 0;
            }
    }
    if(flag)
        cout << "NO" ;//实在没想到是因为No打成了NO，太粗心了
}