illegal, left operand has type 'int (__thiscall Pool::*)(voi

***********那两行我给函数赋值了，他不能直接用来计算么，应该怎么改啊
#include<iostream>
#define PI 3.1415926
using namespace std;
class Pool
{
private:
int pricezha;
int priceguo;
int width;
public:
Pool(int zha,int guo,int _width):pricezha(zha),priceguo(guo),width(_width){}
~Pool(){}
int Getpricezha(){return pricezha;}
int Getpriceguo(){return priceguo;}
int Getwidth(){return width;}
};
void allprice(Pool p1)
{
int r;
cout<<"input r:"<<endl;
cin>>r;
int sum1=0,sum2=0,sum=0;
sum1=p1.Getpricezha*PI*(r+3)*(r+3);//********************************************
sum2=(PI*(r+3)*(r+3)-PI*r*r)*p1.Getpriceguo*p1.Getwidth;//*******************************
sum=sum1+sum2;
cout<<"allprice"<<sum<<endl;
}
int main()
{
Pool p1(25,20,3);
allprice(p1);
return 0;
}