Qt中出现“无法调用匹配功能”错误

Question

It is the first time I am writing classes with Qt. I have stored the declarations in a header file and the source code in in another cpp file but I am getting the error in main of no matching function to call to "Name of class: Name of class ()". I will write down my code and give a print screen of the error below this message. Please I am really struggling with this and the solution would help me a lot. Thanks in advance.

Class header file (cylinder.h)

#ifndef CYLINDER_H
#define CYLINDER_H


class Cylinder
{
private:
    double height;
    double radius;
public:
    Cylinder(double,double);
    double volume();
    double surfaceArea();
};

#endif // CYLINDER_H

Class source code (cylinder.cpp)

#include "cylinder.h"
#include<math.h>
#define PI 3.142

Cylinder::Cylinder(double r,double h) {
    radius=r;
    height=h; }

double Cylinder::volume(){
    return PI*radius*radius*height; }

double Cylinder::surfaceArea(){
    return 2.0*PI*radius*height+PI*radius*radius; }

main.cpp file

#include <iostream>
#include "cylinder.h"
#include "cylinder.cpp"

using namespace std;

int main()
{
    Cylinder c;
    cout<< c.volume(5,5);

    return 0;
}

Error message from Qt

Answer 1

There are two errors in your code:

1. First is that you use the non-existent default constructor, instead of the one you have defined taking two arguments.

2. The second is that you pass two arguments to the volume function, when it doesn't take any arguments.

It seems you have misunderstood how to use objects and member functions.

You code should look something like

Cylinder c(5, 5);     // Pass two arguments here
cout<< c.volume();    // Pass no arguments here

Answer 2

You are missing default constructor

Cylinder() {
...
}

Or construct in main with

Cylinder c(5.,5.);

Also

double Cylinder::volume()

does not accept 2 arguments.

Answer 3

From the picture you posted you can see two errors: first error

-> "candidate expects 2 arguments, 0 provided" in line 9.You should correct with:

Cylinder c(5.0, 5.0);

Second error

In line 10 of main.cpp you are calling method volume passing 2 arguments, but function volume does expect 0 argument. You should change that line with:

cout<< c.volume();

One last thing, why are you including the .cpp file? You don't need it