#include <iostream>
#include <string>

class BankAccount
{
private:
std::string name;
std::string accountnum;
double balance;

public:
BankAccount(std::string client,std::string accnum,double bl=0);
void showAccount(void) const ;
void deposit(double dep);
void withdraw(double wd);
};


BankAccout::BankAccount(std::string client,std::string accnum,double bl)
{
name=client;
accountnum=accnum;
balance=bl;
}


void BankAccount::showAccount(void) const
{
std::cout<<"name:"<<name
<<" accout number:"<<accountnum
<<" balance:"<<balance<<std::endl;
}

void BankAccount::deposit(double dep)
{
balance += dep;
}

void BankAccount::withdraw(double wd)
{
balance += wd;
}


int main()
{
// std::cout << "Hello world!" << std::endl;
// using std::cout;
// using std::string;
using namespace std;
BankAccount cl ("Michael D","786654321",2000.0);
cl.showAccount();

cout<<"after deposit 522.39 into the account:";
cl.deposit(522.39);
cl.showAccount();

cout<<"after withdraw 221.12 into the account:";
cl.withdraw(221.12);
cl.showAccount();
return 0;
}

这两个成员函数是一样的哦！按字面理解应该一个是加一个是减才对吧？在main中引用时输入的都是正值。

#include <iostream>
#include <string>
using namespace std;

class BankAccount
{
private:
string name;
string accountnum;
double balance;

public:

BankAccount(string client="no",string accnum="zero",double bl=0)
{
name=client;
accountnum=accnum;
balance=bl;
}


void showAccount(void) const ;
void deposit(double dep);
void withdraw(double wd);
};



void BankAccount::showAccount(void) const
{
cout<<"name:"<<name<<" accout number:"<<accountnum<<" balance:"<<balance<<std::endl;
}
void BankAccount::deposit(double dep)
{
balance += dep;
}

void BankAccount::withdraw(double wd)
{
balance -= wd;
}

int main()
{
BankAccount h("Michael D","786654321",2000.0);
h.showAccount();

cout<<"after deposit 522.39 into the account:";
h.deposit(522.39);
h.showAccount();

cout<<"after withdraw 221.12 into the account:";
h.withdraw(221.12);
h.showAccount();
return 0;
}