Bank类（c++）

//
// Created by lenovo on 2018/3/20.
//

#ifndef BANK_BANK_H
#define BANK_BANK_H

#include <string>
class bankaccount{
private:
    std::string name;
    std::string accountnum;
    double banlance;
public:
    bankaccount(const std::string&client,
    const std::string&num,double bal=0.0);//constructor
    bankaccount();//default constructor
    ~bankaccount();
    void show() const;
    void deposit();
    void withdraw();
};

#endif //BANK_BANK_H

//
// Created by lenovo on 2018/3/20.
//
#include <iostream>
#include "Bank.h"

bankaccount::bankaccount(const std::string &client,
                         const std::string &num, double bal)
{
    name=client;
    accountnum=num;
    banlance=bal;
}

void bankaccount::show() const {
    using std::cout;
    cout<<"Name: "<<name<<"\n";
    cout<<"Accountnum: "<<accountnum<<"\n";
    cout<<"Banlance: "<<banlance<<"\n";
}

void bankaccount::deposit() {
    std::cout<<"How much do you want to deposit?\n";
    std::cout<<"cash: ";
    double cash;
    std::cin>>cash;
    if(cash>0)
        banlance+=cash;
    else
        std::cout<<"Cash can't be less than 0!\n";
}

void bankaccount::withdraw() {
    std::cout<<"How much do you want to withdraw?\n";
    std::cout<<"cash: ";
    double cash;
    if(cash<banlance)
        banlance-=cash;
    else
        std::cout<<"You can't take more than you have!";
}

bankaccount::bankaccount() {
    name="None";
    accountnum="0000000";
    banlance=0.00;
}

bankaccount::~bankaccount() {
    std::cout<<"Goodbye!  Thanks for your using!\n";
}

#include <iostream>
#include "Bank.h"
using namespace std;

void choice();
void creat(string &name,string &accountnum,double &banlance);

int main() {
    using namespace std;

    //input information
    string name,accountnum;
    double banlance;
    creat(name,accountnum,banlance);
    bankaccount client(name,accountnum,banlance);

    //choice
    choice();
    char ch;
    cin>>ch;
    switch(ch){
        case 'a':
            client.deposit();
            client.show();
            cout<<"Need any other service?";

        case 'b':
            client.withdraw();
            client.withdraw();
            break;
        case 'c':
            cout<<"Sorry! you haven't rooted!";
            break;
        case 'q':
            break;
    }

}

void choice()
{
    using namespace std;

    cout<<"what do you want to do?\n";
    cout<<"a) deposit     b)withdraw\n"
        <<"c)investment   d)quit\n";
}

void creat(string &name,string &accountnum,double &banlance)
{
    cout<<"Welcome to BIlly's Bank!\n";
    cout<<"Please Enter your information first.\n";
    cout<<"Name: ";
    cin>>name;
    cout<<"account number: ";
    cin>>accountnum;
    cout<<"your banlance: ";
    cin>>banlance;
}