C++ Class Practice

// ConsoleApplication1.cpp : 定義主控台應用程式的進入點。
//

#include "stdafx.h"
#include<iostream>
using namespace std;

class Car
{
public:
    void init(double, double);
    double re_gas(){ return gas; };
    double re_eff(){ return eff; };
    void go(double);
private:
    double gas, eff;
};

void Car::init(double E, double G)
{
    gas = G;
    eff = E;
}

void Car::go(double kilo)
{
    if (gas >= kilo/eff)
    {
        gas -= kilo / eff;
        if (gas == 0)
        {
            cout << "油剛好用完了!請加油!\n";
        }
        else
        {
            cout << "跑完了 " << kilo << " 公里，油還剩下 " << gas << " 公升\n";
        }
    }
    else
    {
        cout << "油量不夠!現在的油只夠跑 " << gas*eff << " 公里\n";
    }
}

void main()
{
    Car superone;
    superone.init(20, 30);
    cout << "一台超級車一公升可以跑" << superone.re_eff() << "公里\n"<<"現在有"<<superone.re_gas()<<"公升汽油";

    float length;
    while (superone.re_gas() > 0)
    {
        cout << "請輸入要跑多遠:";
        cin >> length;
        superone.go(length);
    }


}