c++ macro function

#include <iostream>

using namespace std;

#define PI 3.14
#define CircleArea(r){r*r*PI}
void macroFunc8();
#define Multiply(x,y){x*y}
void macroFunc9();

int main()
{
    macroFunc9();
    return 0;
}

void macroFunc9()
{
    int x=100,y=200;
    int z=Multiply(x,y);
    cout<<"x="<<x<<",y="<<y<<",z="<<z<<endl;
    double d1=100.1,d2=200.2;
    double d3=Multiply(d1,d2);
    cout<<"d1="<<d1<<",d2="<<d2<<",d3="<<to_string(d3)<<endl;
    cout<<"Finished in macroFunc9() and now is "<<getTimeNow2()<<endl;
    cout<<to_string(d1*d2)<<endl;
    free(uuidValue);
    free(dtValue);
}

void macroFunc8()
{
    int radius=100;
    double area=CircleArea(radius);
    cout<<"Circle area is "<<area<<endl;
}

g++ -g -std=c++2a -I. h1.cpp -o h1 -luuid