C++编程逻辑讲解step by step：存折和信用卡类。

题目

存折和信用卡类，信用卡是一种存折，可以透支，可以存款。

代码

#include<iostream>
#include<string>
using namespace std;
class passbook
{public:
passbook(string nam,int n,float m)
{name=nam;
num=n;
balance=m;
}
void get_value()
{cin>>name>>num>>balance;}
void display()
{cout<<name<<" "<<num<<" "<<"余额:"<<balance<<" ";}
void deposit();
void withdraw();
protected:
	string name;
	int num;
	float balance;
	};
	void passbook::deposit()
	{
		float sav;
		cout<<"存入金额:";
		cin>>sav;
	balance=balance+sav;
	}
	void passbook::withdraw()
	{
		float withdraw;
		int i;
		cout<<"取款金额:";
		
		for(i=0;i<2;i++)
		{cin>>withdraw;
	if(balance-withdraw<0)
	{cout<<"余额不足，重新输入"<<endl;
	continue;
	}
	else
	{balance=balance-withdraw;
	}
	}
	}
	
	class credit:public passbook
	{public:
	credit(string nam,int n,float m,float a):passbook(nam,n,m)
	{arrears=a;
	}
	void show()
	{display();
	cout<<"透支:"<<arrears<<endl;
	}
	void out()
	{float sd;
cout<<"取款金额:";
	cin>>sd;
	if(arrears+balance-sd<0)
	{arrears=arrears+balance-sd;
	balance=0;}
	else
	{balance=balance-sd;}
	}
	private:
		float arrears;
	};
	int main()
	{credit studl("小陈",3423132,1000,0);
	studl.show();
	studl.deposit();
	studl.show();
	studl.out();
	studl.show();
	passbook stul2("马云",43842238,100);
	stul2.display();
	stul2.deposit();
	stul2.display();
	stul2.withdraw();
	stul2.display();
	return 0;
	}