code/class/class_test.cpp

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

using namespace std;

/*
int main(){
    int a,b,c;

    cin >>a>>b>>c;

    if (a = 1)
    {
        cout <<"no";
        Sleep(1000);
        return 0;
    }
    

    if ((a+b) > c)
    {
        cout <<"yes";
        Sleep(1000);
        return 0;
    }else if ((a+c) > b)
    {
        cout <<"yes";
        Sleep(1000);
        return 0;
    }else if ((b+c) > a)
    {
        cout <<"yes";
        Sleep(1000);
        return 0;
    }else
    {
        cout <<"no";
        Sleep(1000);
        return 1;
    }
    
    return 0;
}

int main(){  //三角形判断
    int a,b,c;

    cin >>a>>b>>c;

    if ((a+b > c) && (a+c > b) && (b+c > a))
    {
        cout <<"yes";
    }else
    {
        cout <<"no";
    }
    
    return 0;   
}

int main() {
    srand(static_cast<unsigned int>(time(nullptr))); // 初始化随机数种子
    int random_number = rand() % 5 + 1; // 生成 1 到 5 之间的随机数
    cout <<random_number<<endl;
    int player_cin;

    cout <<"输入你猜的数字,1-5之间"<<endl;
    cin >> player_cin;

    if (player_cin == random_number)
    {
        cout <<"恭喜您,中奖了!奖金10元!"<<endl;
        return 0;
    }else
    {
        cout <<"没中奖!请付费2元"<<endl;
        cout <<"中奖号码是:"<<random_number<<endl;
        return 1;
    }
    
    return 0;
}

int main(){
    int n = 6;

    //cin >> n;

    int sum = n * (n+1) /2;

    cout <<sum;
    return 0;
}*/

int main(){
    int count = 0;
    for (int i = 1; i < 1000; ++i)
    {
        if (to_string(i).find('3') != string::npos)
        {
            count++;
        }
    }
    cout <<count<<endl;
    
    return 0;
}