账户Account类文件编写（static成员使用）

static类成员是该类所有成员共享一份的数据，一处修改了，全部变更；
static成员函数只能调用static成员数据；
static const整形int，char，可以在类内声明和初始化，类外不必再声明（跟编译器有关）
static const非整型和 static 普通成员，必须在类内声明，在类外初始化！

Account.h 头文件

#ifndef ACCOUNT_H
#define ACCOUNT_H
#include<string>
// using namespace std;
class Account
{
public:Account(std::string own, double amnt){owner = own;amount = amnt;}void applyint()	//计算余额{amount += amount * intersetRate;}static double rate()	//返回当前利率{return intersetRate;}static void rate(double newRate)	//设置新的利率{intersetRate = newRate;}double deposit(double amnt)	//存款{amount += amnt;return amount;}bool withdraw(double amnt)	//取款{if(amount < amnt)return false;else{amount -= amnt;return true;}}double getBalance()	//查询余额{return amount;}
private:std::string owner;double amount;static const int a = 1;static const char bkground = '!';	//static const 整型可以直接在类内定义初始化static double intersetRate;const static double initrate;static const std::string s1;static const float f1;	//static const 非整型and static 普通成员，要在类内声明，在类外初始化
};
double Account::intersetRate = 0.025;
const double Account::initrate = 0.01;
const std::string Account::s1 = "china";
const float Account::f1 = 1.0;#endif

main_Account.cpp 主函数

#include"Account.h"
#include<iostream>
using namespace std;int main()
{Account cmm("chenmm", 0), nhl("niuhl", 0);cout << cmm.rate() << " " <<nhl.rate() << endl;cmm.rate(0.035);cout << cmm.rate() << " " <<nhl.rate() << endl;cmm.deposit(100);nhl.deposit(200);cout << cmm.getBalance() << " " <<nhl.getBalance() << endl;cmm.withdraw(50);nhl.withdraw(210);cout << cmm.getBalance() << " " <<nhl.getBalance() << endl;cmm.applyint();nhl.applyint();cout << cmm.getBalance() << " " <<nhl.getBalance() << endl;
}