C++课本第四章例题

个人银行账户管理程序

#include<iostream>
#include <cmath>
using namespace std;
class SavingsAccount{                  //储蓄账户类 
    private:
        int id;                         //账号 
        double balance;                 //余额 
        double rate;                    //存款的年利率 
        int lastDate;                   //上次变更余额的时期 
        double accumulation;             //余额按日累加之和
        //记录一笔账，date为日期，amount为金额，desc为说明
        void record(int date,double amount);
        //获得到指定日期为止的存款金额按日累计值
        double accumulate(int date)const{
           return accumulation+balance*(date-lastDate);
        } 
    public:
        //构造函数
        SavingsAccount(int date,int id,double rate);
        int getId(){
            return id;
        } 
        double getBalance(){
            return balance;
        }
        double getRate(){
            return rate;
        }
        void deposit(int date,double amount);           //存入现金 
        void withdraw(int date,double amount);          //取出现金
        //结算利息，每年一月一日调用一次该函数
        void settle(int date);
        //显示账户信息
        void shouw(); 
}; 
//SavingsAccount类相关成员函数的实现
SavingsAccount::SavingsAccount(int date,int id,double rate):id(id),balance(0),rate(rate),lastDate(date),accumulation(0){
    cout<<date<<"\t#"<<id<<"is created"<<endl;
} 
void SavingsAccount::record(int date,double amount){
    accumulation=accumulate(date);
    lastDate=date;
    amount=floor(amount*100+0.5)/100;
    balance+=amount;
    cout<<date<<"\t#"<<id<<"\t"<<amount<<"\t"<<balance<<endl;
}
void SavingsAccount::deposit(int date,double amount){
    record(date,amount);
}
void SavingsAccount::withdraw(int date,double amount){
    if(amount>getBalance())
    cout<<"error:not enough money"<<endl;
    else
    record(date,-amount);
}
void SavingsAccount::settle(int date){
    double interest=accumulate(date)*rate/365;    //计算年息
    if(interest!=0)
    record(date,interest);
    accumulation=0;
}
void SavingsAccount::shouw(){
    cout<<"#"<<id<<"\tBalance: "<<balance<<endl;
}
int main()
{
    //建立几个账户
    SavingsAccount sa0(1,21325302,0.015);
    SavingsAccount sa1(1,58320212,0.015);
    //几笔账目
    sa0.deposit(5,5000);
    sa1.deposit(25,10000);
    sa0.deposit(45,5500);
    sa1.withdraw(60,4000);
    //开户后第九十天到了银行的计息日，结算所有账户的年息
    sa0.settle(90);
    sa1.settle(90);
    //输出各个账户的信息
    sa0.shouw();
    cout<<endl;
    sa1.shouw();
    cout<<endl;
    return 0; 
}