关于#c++#的问题：改代码

Question

请问

#include<iostream>
#include<cmath>
using namespace std;
const double PI=3.14;
double r;
double V1;
double V2(double PI,double r,double V1)
{
    cin>>r;
    V1=PI*3/4*pow(r,3);
    cout<<V2;
}
int main()
{
    V2();
    return 0;
}

怎么该？

Answer 1

#include<iostream>
#include<cmath>
using namespace std;
const double PI=3.14;
double r;
double V1;
double V2()
{
    cin>>r;
    V1=PI*3/4*pow(r,3);
    cout<<V1;
}
int main()
{
    V2();
    return 0;
}