Writing a class but having trouble

[Billy George]

So the problem is the value of m in the magnitude function. The value is not transferring out to be used at any of the argument function.

#include <cmath>
#include <cstdlib>
#include <iostream>
const double pi=3.141592654;

using namespace std;

class Point{

public:
       Point(){}
       Point(float, float, float);
       
       //double getx() const { return x;}
       //double gety() const { return y;}
       //double getz() const { return z;}
       float magnitude() const;  //determine each points magnitude to origin
       float argumentx() const;   //Angle of the vector in degrees
       float argumenty() const;   //Angle of the vector in degrees
       float argumentz() const;   //Angle of the vector in degrees
       float m;
private:
        float x,y,z; 
};

//This is the point object, initialize the data members to parameter values
//Constructor definition

Point::Point(float xval, float yval, float zval){
        x=xval;
        y=yval;
        z=zval;        
}

//This is the magnitude
//Member function definition

float Point::magnitude() const
{
                 float m=sqrt(x*x+y*y+z*z);
                  return m;   
}

//This is the angle member function definition

float Point::argumentx() const
{
                 float angX; //Angle of vector to X-axis 
                 angX=acos(x/m)*(180/pi);
                 cout<<angX<<" Degrees in respect to X-axis.\n";
                 
                 return 0;
                 }
float Point::argumenty() const
{
                 float  angY; //Angle of vector to y-axis 
                 angY=acos(y/m)*(180/pi);
                 cout<<angY<<" Degrees in respect to Y-axis.\n";
                 return 0;
                 }
float Point::argumentz() const
{
                 float angZ; //Angle of vector to z-axis
                 cout<<z<<endl<<m<<endl<<pi<<" Z point";
                 angZ=acos(z/m)*(180/pi);
                 cout<<angZ<<" Degrees in respect to Z-axis.\n";
                 return 0;
                 }


int main(int argc, char *argv[])
{
    //Point point1;
    float Xpoint, Ypoint, Zpoint; //This is the user input
    
    cout<<"Describe the point by entering the x-axis, y-axis,"
        <<"z-axis"<<endl<<"-->";
    cin>>Xpoint>>Ypoint>>Zpoint;
    
    Point point1(Xpoint, Ypoint, Zpoint);
    
    cout<<"The magnitude of the point is "<<point1.magnitude()<<endl;
    cout<<point1.argumentx();
   cout<<point1.argumenty();
   cout<<point1.argumentz();
   
    system("PAUSE");
    return EXIT_SUCCESS;
}

[Stewbond]

I see...

You calculate m, however it is a local variable only. It isn't a private member and therefore cannot be used by the other functions in the class.

To solve this, m should be a private member. Replace line 23 with: float x,y,z,m; and replace line 40 with: m = sqrt(x*x+y*y+z*z);

[Billy George]

Thank you, I am beginning to understand the private use now. It works.

[Stewbond]

It sure does!

Private is great if you are doing internal calculations and you don't want "others" to be able to access intermediate calculations.