CODEWITHSUNDEEP
c++
Tomasz Jankowski
Tomasz Jankowski

Reputation: 38

no known conversion 'float (MyClass::*)' to 'float (*)'

I am supposed to write a program which has to generate a triangle function, calculate the derivative using forward and backward divided differences and differentiate the triangle function. So, I wrote some code and have only one problem:

include\MyClass.h|12|note: no known conversion for argument 1 from 'float (MyClass::)(int, float, float)' to 'float ()(int, float, float)'|

My code:

main.cpp

#include <iostream>
#include "MyClass.h"
using namespace std;

int main()
{
    MyClass object (3,4,2,0.1);

    for (float i=object.x; i<2.5; i+=0.01)
    {
        cout << object.Triangle(10, 3.14, i) << " ";
    }

    cout << "////////////////////";

    for (float i=object.x; i<2.5; i+=0.01)
    {
        cout << object.Derivative(&object.Triangle, i, object.con) << " ";
    }
}

MyClass.h

#ifndef MYCLASS_H
#define MYCLASS_H


class MyClass
{
    public:
        MyClass();
        MyClass(int k_max, float omega, float x, float con);
        ~MyClass();
        float Triangle (int k_max, float omega, float x);
        float Derivative (float (*w) (int k_max, float omega, float x), float var, float con);
        float DerivativeCntr (float (*w) (int k_max, float omega, float x), float var, float con);
        int k_max;
        float omega, x, result, con;
};

#endif // MYCLASS_H

MyClass.cpp

#include "MyClass.h"

MyClass::MyClass() {}
MyClass::~MyClass() {}

MyClass(int K_max, float Omega, float X, float Con)
{
    k_max=K_max;
    omega=Omega;
    x=X;
    con=Con;
}

///////////////////////////////////////////////

float Triangle (int k_max, float omega, float x)
    {
        result=0;

        for int (i=0; i<=k_max; i++)
        {
            result += ( 8*pow(-1, i)*(sin((2*i+1)*omega*x ) / ( pow(2*i+1, 2) * pow(M_PI, 2) )
        }
        return result;
    }

///////////////////////////////////////////////

float Derivative (float (*w) (int k_max, float omega, float x), float var, float con)
    {
        float result = (w(10, 3.14, var+con) - w(10, 3.14, var))/var;
        return result;
    }

///////////////////////////////////////////////

float DerivativeCntr (float (*w) (int k_max, float omega, float x), float var, float con)
    {
        float result=(w(10, 3.14, var)-w(10, 3.14, var-con))/2*var;
        return result;
    }

I would really appreciate your help, thanks!

EDIT: I've got this program working, but it's recommended to use a class and required to use a pointer to the function. That's my non object-oriented code: https://ideone.com/mtPLAo

Upvotes: 1

Views: 210

Answers (1)

user1781434
user1781434

Reputation:

You have several errors of syntactical nature in your code.

In MyClass.h, change into

float Derivative (float *w, int k_max, float omega, float x, float var, float con);
float DerivativeCntr (float *w, int k_max, float omega, float x, float var, float con);

In MyClass.cpp, all member functions should be prefixed by MyClass:: and also the same for the constructor that takes arguments.

Upvotes: 0

Related Questions