#include<iostream>
#include<windows.h>

using namespace std;
void while_on();
void while_off();

int main(){
    cout <<"请选择"<<endl;
    cout <<"1.不带循环版"<<endl<<"2.带循环版"<<endl<<"3.退出"<<endl;
    cout <<">>>";
    int count;
    cin >>count;

    if (count == 1)
    {
        while_off();
    }else if (count == 2)
    {
        while_on();
    }else if (count == 3)
    {
        return 0;
    }else
    {
        cout <<"无效的选择!"<<endl;
        Sleep(1850);
        return 1;
    }
    return 0;    
}

void while_off(){
    cout <<"现在模式是 不带循环版"<<endl;
    Sleep(1250);

    cout <<"请输入一个正整数:";
    long long num;
    cin >>num;

    long long count1 = 0;
    do
    {
        num /= 10;
        count1++;
    } while (num != 0);
    
    cout <<count1<<endl;
    Sleep(2000);
}

void while_on(){
    cout <<"现在模式是 带循环版"<<endl;
    Sleep(1250);

    while (TRUE)
    {
        cout <<"请输入一个正整数:";
        long long num;
        cin >>num;

        long long count2 = 0;

        do
        {
            num /= 10;
            count2++;
        } while (num != 0);
        
        cout <<count2<<endl;
        Sleep(2000);        
    }
}