/*5.创建一个SavingAccount类。使用一个static数据成员
annualInterestRate保存每个存款者的年利率。类的每个
对象都包含一个private数据成员savingsBalance,用以指
示存款者目前的存款金额。该类提供成员函数calculateMonthlyInterest,
它将余额乘以annualInterestRate再除以12来计算月利息,这个利息应该
加到savingsBalance中。该类还提供一个static成员函数
ModifyInterestRate,它将static的annualInterestRate设置
为一个新值。编写一个驱动程序测试该类,实例化SavingAccount类
的两个对象save1和save2,余额分别是20000元和30000元,将
annualInterestRate设置为3%,然后计算月利率并打印每个存款者
的新余额。接着再将annualInterestRate设置为4%,计算下一个月的
利息并打印每个存款者的新余额。
*/
#include<iostream>
using namespace std;
class SavingAccount{
private:
static double annualInterestRate;
double savingsBalance;
public:
SavingAccount(double a);
static void ModifyInterestRate(double b);
double calculateMonthlyInterest();
void show();
};
SavingAccount::SavingAccount(double a)
{
savingsBalance=a;
}
void SavingAccount::ModifyInterestRate(double b)
{
annualInterestRate=b;
}
double SavingAccount::calculateMonthlyInterest()
{
double t;
t=savingsBalance*annualInterestRate;
t=t/12;
savingsBalance=savingsBalance+t;
return savingsBalance;
}
void SavingAccount::show()
{
cout<<"存款者的新余额为:"<<endl;
cout<<savingsBalance<<endl;
}
double SavingAccount::annualInterestRate=0.0;
int main()
{
SavingAccount save1(20000);
save1.ModifyInterestRate(0.03);
save1.calculateMonthlyInterest();
save1.show();
SavingAccount save2(30000);
save2.ModifyInterestRate(0.03);
save2.calculateMonthlyInterest();
save2.show();
SavingAccount save3(20000);
save3.ModifyInterestRate(0.04);
save3.calculateMonthlyInterest();
save3.show();
SavingAccount save4(30000);
save4.ModifyInterestRate(0.04);
save4.calculateMonthlyInterest();
save4.show();
return 0;
}