#include<iostream.h>
class cylinder{
public:
cylinder ( double x,double y);
double get_volume ( double x,double y);
void vol ( );
private:
double radius,height;
double volume;
};

double cylinder::cylinder ( double x,double y){
radius=x; height=y;
}
double cylinder::get_volume ( double x,double y)
{
return volume=3.14*x*x*y;
}
void cylinder::vol ( )
{
cout<<"volume="<<volume<<endl;
}
void main(){
cylinder ob (2.0,3.0);
ob.vol();
}

请把你们的高见写下来...

是错了还是咋地？
怎么没计算体积啊？
void main(){
cylinder ob (2.0,3.0);
ob.get_volume();
ob.vol();
}

先要说明错误

再看看吧

请把你们的高见写下来...
我也郁闷了,你都没说啥回事呢？

没看懂

看不懂

double cylinder::cylinder ( double x,double y){
radius=x; height=y;
}


构造函数不能有返回值
cylinder::cylinder ( double x,double y){
radius=x;
height=y;
volume=3.14*x*x*y;
}

#include<iostream>
using namespace std;

class cylinder
{
public:
cylinder ( double x,double y);
double get_volume ();
void vol ( );
private:
double radius,height;
double volume;
};

cylinder::cylinder ( double x,double y)
{
radius=x; height=y;
}
double cylinder::get_volume ()
{
return volume=3.14*radius*radius*height;
}
void cylinder::vol ( )
{
cout<<"volume="<<volume<<endl;
}
int main()
{
cylinder ob (2.0,3.0);
ob.get_volume();
ob.vol();

return 0;
}

1. 构造函数没有返回值
2. 主函数中还没有运行get_volume()没有对体积进行计算
3. 你的get_volume()函数本身怎么还带参数啊