我正在尝试调用一个函数。 这些愚蠢的编译错误的原因是什么？

我正在尝试运行我编写的这个c++程序。我在Visual C++中得到以下错误：

1>c： \users\server\sdesktop\problem7\problem7\main.cpp（26）：错误C3867:"Payment:：getamount"：函数调用缺少参数列表；使用'&Payment:：getamount'以创建指向成员的指针

1>c： \users\server\sdesktop\problem7\problem7\main.cpp（74）：错误C3867:"cashPayment:：paymentDetails"：函数调用缺少参数列表；使用'&cashPayment:：paymentDetails'创建指向成员的指针

1>c： \users\server\sdesktop\problem7\problem7\main.cpp（75）：错误C3867:"CreditCardPayment:：paymentDetails"：函数调用缺少参数列表；使用'&CreditCardPayment:：paymentDetails'创建指向成员的指针

代码是：

#include <iostream>
#include <cstring>
using namespace std;
class Payment
{
private: float amount;
public: Payment(float=0.0);
        void paymentDetails();
        float getamount();
        void setamount(float);
};

Payment::Payment(float a)
{
    setamount(a);
}
void Payment::setamount(float a){amount=a;}
float Payment::getamount(){return amount;}
void Payment::paymentDetails()
{
    cout<<"The amount of payment is : "<<getamount<<"$"<<endl;
}
class cashPayment: public Payment
{
public: cashPayment(float=0.0);
        void paymentDetails();
};
cashPayment::cashPayment(float a):Payment(a){};
void cashPayment::paymentDetails()
{
    cout<<"The payment in cash is : "<<getamount()<<"$"<<endl;
}
class CreditCardPayment: public Payment
{
private: char* name;
         int creditnumber;
         int day,month,year;
public: CreditCardPayment(char[]=" ",int=0, int=0, int=0, int=0 ,float=0.0);
        void paymentDetails();
};
CreditCardPayment::CreditCardPayment(char* n, int cn, int d, int m, int y, float a):Payment(a)
{
    int l=strlen(n);
    name = new char[l+1];
    strncpy(name,n,l);
    name[l]='';
    creditnumber=cn;
    day=d;
    month=m;
    year=y;
}
void CreditCardPayment::paymentDetails()
{
    cout<<"Credit Card Holder Information & Payment: "<<endl;
    cout<<"Name is "<<name<<endl;
    cout<<"Credit Number is "<<creditnumber<<endl;
    cout<<"Expiration Date (Day / Month / Year) is "<<day<<"/"<<month<<"/"<<year<<endl;
    //cout<<"Payment is "<<Payment::getamount()<<"$"<<endl;
}
int main()
{
    CreditCardPayment cc1("Mohammad",936623,21,9,2011,3000);
    cashPayment cp1(4500);
    cp1.paymentDetails;
    cc1.paymentDetails;
    system("pause");
    return 0;
}