静态成员

类型 类名:：变量名=值；

#include<iostream>
#include<string>
using namespace std;
class ACCOUNT
{
    string m_name;      //户名
    string m_account;   //账号
    double m_balance;   //余额
    static double m_rate; //利率
public:
    ACCOUNT(string name, string account, double balance)
    {
        m_name = name;
        m_account = account;
        m_balance = balance;
    }
    void save(double money) //存钱
    {
        m_balance += money;
    }
    void draw(double money) //取钱
    {
        if (money > m_balance)
        {
            cout << "余额不足" << endl;
        }
        m_balance -=money;
    }
    void query() const  //查询
    {
        cout << "户名:" << m_name << endl;
        cout << "账号:" << m_account << endl;
        cout << "余额:" << m_balance << endl;
    }
    void collect()  //汇总
    {
        m_balance *= (1 + m_rate / 100);//加利息
    }
    static void adjust(double rate) //设置利息
    {
        if (rate > 0)
        {
            m_rate = rate;
        }
    }
};
//类外初始化(定义)
double ACCOUNT::m_rate = 0.2;
int main()
{
    ACCOUNT man("梦凡", "622848-888888-888888", 6666);
    man.draw(2000); //取钱
    man.query();    //业务查询

    ACCOUNT man2("梦爱", "622848-666666-6666666", 8888);
    man2.save(1000);    //存钱
    man2.query();       //业务查询
    cout << "------------" << endl;
    man.collect();      //按月结算利息
    man.query();        //业务查询
    man2.collect();     //按月结算利息
    man2.query();       //业务查询
    //ACCOUNT::adjust(0.5); //设置利率
    man.adjust(0.4);        //设置利率
    return 0;
}
//打印结果
户名:梦凡
账号:622848-888888-888888
余额:4666
户名:梦爱
账号:622848-666666-6666666
余额:9888
------------
户名:梦凡
账号:622848-888888-888888
余额:4675.33
户名:梦爱
账号:622848-666666-6666666
余额:9907.78