Hello I have trouble access STL complex + binary operator, my fVector is derived from std::complex, I try to call the std::complex binary + operator function to do the calculation, but I say it does have member of operator +.
ok update more of my code as request, there is 3 file which is fVector2D_test.cpp fVector2D.cpp and fVector2D.hpp
#include <iostream>
#include <complex>
#include "fVector2D.hpp"
//using namespace std;
using std::cout;
using std::endl;
int main()
{
/*fVector2D u, v(2.4f, 7), w(v);
cout << v.X(); u = fVector2D(u.X(), v.Y());
cout << u <<endl;
// v.Y() = 3.4f; // compiler error
fVector2D a(1, 2), b(2, 3);
float dot = a*b;
cout << dot <<endl;
cout << fVector2D::EX << "+" << fVector2D::EY;*/
fVector2D v(3,4.1f), u(1.2f,8.5f);
fVector2D w = u + v;
cout << w << endl;
//w = exp(std::complex<float>(0,0.2f))*v;
//cout << w << endl;
// cout << (u*v) << endl;
//cout << fVector2D::EX << endl;
//cout << fVector2D::EY << endl;
//cout << abs(v) << endl;
return 0;
}
#include <complex>
class fVector2D : public std::complex<float>
{
public:
fVector2D(float x=0, float y =0);
fVector2D(const fVector2D& floatVector2D);
float X()const;
float Y()const;
//static const EX;
//static const EY;
private:
};
fVector2D operator+(const fVector2D& , const fVector2D&);
#include "fVector2D.hpp"
fVector2D::fVector2D(float x, float y)
: std::complex<float>(x, y)
{
}
fVector2D::fVector2D(const fVector2D& floatVector2D)
: std::complex<float>(floatVector2D)
{
}
float fVector2D::X()const
{
return real();
}
float fVector2D::Y()const
{
return imag();
}
fVector2D operator+(const fVector2D& lhs, const fVector2D& rhs)
{
return std::complex<float>::operator+(lhs,rhs);// compile error , no operator + in the member
}
+ for complex numbers is a free function, not a member function. That is why you can not access it using complex<float>:: syntax.
Beside this problem your code has other problems(I have trouble seeing any real scenario where one would want to inherit from std::complex), but that is outside the scope of the question.
Related
My task is to practice inheritance, putting all the classes in separate files. I have a base class Circle and a derived class Cylinder.
What I'm stuck on is trying to display on the screen the result of my calculated area and volume for an object B of a Cylinder type. I found a way to do that for a Circle, though it doesn't work for my Cylinder.
circle.h
#pragma once
#include <iostream>
class Circle {
public:
float r;
Circle();
Circle(float r);
Circle circumference();
Circle area();
void view();
void getArea();
void getCircum();
};
circle.cpp
#include "circle.h"
#include <cmath>
using namespace std;
Circle::Circle() : r(5) {
cout << "Default constructor has been called for a circle\n";
}
Circle::Circle(float r) {
this->r = r;
cout << "Constructor with parameters has been called for a circle\n";
}
void Circle::view() {
cout << "Radius = " << r << endl;
}
Circle Circle::circumference() {
return 2 * M_PI * r;
}
Circle Circle::area() {
return M_PI * pow(r, 2);
}
void Circle::getArea() {
cout << "Area = " << r << " m^2";
}
void Circle::getCircum() {
cout << "Circumference = " << r << " m";
}
cylinder.h
#pragma once
#include <iostream>
#include "circle.h"
class Cylinder : public Circle {
public:
float h;
Cylinder();
Cylinder(float r, float h);
void view();
double area();
double volume(float r, float h);
void getArea();
void getVolume();
};
cylinder.cpp
#include "cylinder.h"
#include <cmath>
using namespace std;
Cylinder::Cylinder() : h(7) {
cout << "Default constructor has been called for a cylinder\n";
}
Cylinder::Cylinder(float r, float h) : Circle(r) {
this->h = h;
cout << "Constructor with parameters has been called fo a cylinder\n";
}
void Cylinder::view() {
Circle::view();
cout << "Height = " << h << endl;
}
double Cylinder::area() {
return 2 * M_PI * r * h;
}
double Cylinder::volume(float r, float h) {
return M_PI * pow(r, 2) * h;
}
void Cylinder::getArea() {
cout << "Area = " << h;
}
void Cylinder::getVolume() {
cout << "Volume = " << h;
}
main.cpp
#include <iostream>
#include "circle.h"
#include "cylinder.h"
using namespace std;
int main() {
Circle A;
A.view();
Circle A1(8);
A1.view();
Cylinder B;
B.view();
Cylinder B1(4, 6);
B1.view();
//A.area().getArea();
//cout << endl;
//A.circumference().getCircum();
//cout << endl;
//A1.area().getArea();
//cout << endl;
//A1.circumference().getCircum();
B.area().getArea();
return 0;
}
The error that I'm getting:
main.cpp: In function ‘int main()’:
main.cpp:26:14: error: request for member ‘getArea’ in ‘B.Cylinder::area()’, which is of non-class type ‘double’
26 | B.area().getArea();
| ^~~~~~~
I feel like neither my code in main() for instance B, nor my methods getArea() and getVolume() in class Cylinder, are correct. And there is probably a better approach to do the same for an object A and A1 of a Circle type, though the code I commented out actually works.
I know that this is a dumb question, and such things should be quite straightforward, but I am trying to learn and would be grateful for any advice on how I can fix this.
Well, the reason you are getting the error message:
main.cpp: In function ‘int main()’:
main.cpp:26:14: error: request for member ‘getArea’ in ‘B.Cylinder::area()’, which is of non-class type ‘double’
26 | B.area().getArea();
| ^~~~~~~
Is because you are basically doing this:
auto _ = B.area();
So here, _ deduces to be a double, and then you do:
_.getArea();
You are trying to access a member function from a double, and double doesn't have any member functions.
You probably meant to do this instead:
auto x = B.area();
B.h = x;
B.GetArea();
This assigns the area of B.area() to a variable x, and assigns x to B.h. B's member function then gets called and outputs the area.
In your getArea() function, instead of saying:
cout << "Area = " << endl;
Just say:
cout << "Area = " << area() << endl;
Then in your main.cpp, just call B.getArea().
Hope this helps!
I have been trying to print the points like The position of the point is (1,2) from using class, but I can't figure out a way to do it. I simply can't find a way to return two numbers like that, but the problem requires solution that way.
#include <iostream>
using namespace std;
class MyPoint{
public:
int x,y,radius;
MyPoint()
{
x=0;
y=0;
}
MyPoint(int x1,int y1)
{
x=x1;
y=y1;
}
int point_display()
{
char st=(x,y);
return st;
}
int getAdd()
{
return x+y;
}
};
int main()
{
MyPoint mypoint;
cin>>mypoint.x>>mypoint.y;
cout<<"The position of the point is "<<mypoint.point_display()<<endl;
cout<<"The sum of the coordinates is "<<mypoint.getAdd()<<endl;
return 0;
}
The usual solution to this is to provide an overload of operator << for class MyPoint to print the point.
Something like this:
#include <iostream>
using namespace std;
class MyPoint{
public:
int x,y,radius;
MyPoint()
{
x=0;
y=0;
}
MyPoint(int x1,int y1)
{
x=x1;
y=y1;
}
int getAdd()
{
return x+y;
}
friend ostream& operator << (ostream& os, const MyPoint& p);
};
ostream& operator << (ostream& os, const MyPoint& p)
{
os << p.x << ", " << p.y;
return os;
}
int main()
{
MyPoint mypoint { 1,2 };
cout<<"The position of the point is "<<mypoint<<endl;
cout<<"The sum of the coordinates is "<<mypoint.getAdd()<<endl;
return 0;
}
Output:
The position of the point is 1, 2
The sum of the coordinates is 3
Live demo
Your point_display could return a string composed of the 2 values:
std::string point_display()
{
return std::string{"("} + std::to_string(x)
+ "," + std::to_string(x) + ")";
}
Alternatively, as your question asks about returning 2 values, the function could return a pair:
std::pair<int,int> point_display ()
{
return {x,y};
}
and in main, you could do:
auto [x, y] = mypoint.point_display();
cout << "The position of the point is ("
<< x << "," << y << ")" << endl;
However, since the data members are public, you could just destructure the object and print out the values in main:
auto [x, y, radius] = mypoint;
cout << "The position of the point is ("
<< x << "," << y << ")" << endl;
If all you want to do is print the coordinates, you could have the method do it:
void point_display()
{
cout << "(" << x << ", " << y << ")";
}
...
cout<<"The position of the point is ";
mypoint.point_display();
cout << endl;
If you really want to return the coordinates, you could have separate accessors ("getters"):
int getX()
{
return x;
}
int getY()
{
return y;
}
or use references:
void getCoordinates(int &rx, int &ry)
{
rx = x;
ry = y;
}
...
int a, b;
mypoint.getCoordinates(a, b);
cout << a << " " << b << endl;
I am trying to convert different coordinate systems. From polar to rectangular and vice versa. My pol_to_rect()function is not working properly. It is giving very small values(~10^(-44)) after converting and also before converting. There might be some problem while using the sin() and cos() functions. The rect_to_pol() is working fine for positive values.
Edit - When I changed atan() to atan2() how can I incorporate other values of x and y.
#include <iostream>
#include <cmath>
using namespace std;
#define PI 3.1415926
class Polar; // Forward declaration
class Rectangular {
private:
float x, y;
public:
Rectangular() {} // default constructor
Rectangular(float mv_x, float mv_y) {
x = mv_x;
y = mv_y;
}
void showData() const;
Polar rect_to_pol();
float& get_x() {
return x;
}
float& get_y() {
return y;
}
};
void Rectangular::showData() const {
cout << "--Rectangular--" << endl;
cout << "x: " << x << "\t" <<"y: " << y << endl;
}
class Polar {
private:
float r;
float theta;
public:
Polar() {} // default constructor
Polar(float mv_r, float mv_theta) {
r = mv_r;
theta = mv_theta;
}
void showData();
Rectangular pol_to_rect();
float& get_r(){
return r;
}
float& get_theta() {
return theta;
}
};
void Polar::showData() {
cout << "--Polar--" << endl;
cout << "r:" << r << "\t" << "Theta(Radians):" << theta << endl;
}
Rectangular Polar::pol_to_rect() {
Rectangular temp;
temp.get_x() = r * cos(theta*(PI/180.0)); // in degrees
temp.get_y() = r * sin(theta*(PI/180.0));
return temp;
}
Polar Rectangular::rect_to_pol() {
Polar temp;
temp.get_r() = sqrt(pow(x, 2) + pow(y, 2));
temp.get_theta() = atan2(y, x);
return temp;
}
int main()
{
Rectangular r1(-1, -1), r2;
Polar p1(12.0, 30.0), p2;
r1.showData();
p2 = r1.rect_to_pol();
cout << "After Conversion (RECT TO POLAR)->" << endl;
p2.showData();
p1.showData();
r2 = p1.pol_to_rect();
cout << "After Conversion (POLAR TO RECT)" << endl;
r2.showData();
return 0;
}
In my program I have created a constructor called Point with two values. I also have a set, get, scale and translate function. I'm trying to create a function that allows me to get the distance between the object and another point. I'm have trouble with it though any help would be brilliant.
#ifndef POINTMODEL
#define POINTMODEL
#define POINTDEB UG
#include <iostream>
#include <string.h>
using namespace std;
class Point {
public:
Point(void);
Point(double anX, double aY);
~Point();
void setPoint(double anX, double aY);
double getX();
double getY();
double scaleX(double theX);
double scaleY(double theY);
void translate(double theX, double theY);
void distance(const Point& aPoint);
protected:
private:
double theX;
double theY;
};
inline Point::Point(void)
{
theX = 1;
theY = 1;
cout << "\n The default constructor was called" << endl;
}
inline Point::Point(double anX, double aY)
{
cout << "\n regular constructor called";
}
inline Point::~Point()
{
cout << "\n the destructor was called" << endl;
}
inline void Point::setPoint(double anX, double aY)
{
theX = anX;
theY = aY;
}
inline double Point::getX()
{
return theX;
}
inline double Point::getY()
{
return theY;
}
inline double Point::scaleX(double theX)
{
return theX;
}
inline double Point::scaleY(double theY)
{
return theY;
}
inline void Point::translate(double offSetX, double offSetY)
{
cout << "X is translated by : " << offSetX << endl;
cout << "Y is translated by : " << offSetY << endl;
}
inline void Point::distance(const Point& aPoint)
{
}
#endif
Cpp file:
#include "Point.h"
using namespace std;
int main(void)
{
cout << "\n main has started" << endl;
//Point myPoint;
Point myPoint(1, 1);
myPoint.setPoint(1, 1);
cout << "\n The value for X is : " << myPoint.getX() << endl;
cout << "\n The value for Y is : " << myPoint.getY() << endl;
cout << "\n X scaled by 2 is : " << myPoint.scaleX(2) << endl;
cout << "\n Y scaled by 2 is : " << myPoint.scaleY(2) << endl;
myPoint.translate(2, 3);
cout << "\n main has finished" << endl;
return 0;
}
You need to make your Point::getX() and Point::getY() functions const like so:
inline double Point::getX() const
{
return theX;
}
If they are not const you cannot call them when the parameter is a const reference.
Then the distance is (changed return from void to double):
double distance(const Point & aPoint) const
{
const double x_diff = getX() - aPoint.getX();
const double y_diff = getY() - aPoint.getY();
return std::sqrt(x_diff * x_diff + y_diff * y_diff);
}
I have deliberately not used std::pow since the exponent is 2.
You also need to include <cmath> for std::sqrt.
I am having issues displaying coordinates that are read into a class. This is my first time using classes so please be understanding!
Here is what I have so far:
#include <iostream>
using namespace std;
class Vector{
private:
float x;
float y;
public:
Vector(float f1, float f2)
{
x=f1;
y=f2;
}
Vector(){}
float display()
{
Vector v;
cout << "(" << v.x << "," << v.y << ")" << endl;
return 0;
}
};
int main()
{
Vector v1(0.5, 0.5);
cout << "v1 ";
v1.display();
system("pause");
return 0;
}
It prints
v1 (-1.07374e+008,-1.07374e+008)
Your problem is that you are not printing out the coordinates of the Vector you created in main() but a default created one in your function. Instead of
float display()
{
Vector v;
cout << "(" << v.x << "," << v.y << ")" << endl;
return 0;
}
You need
float display()
{
//Vector v; remove this
cout << "(" << x << "," << y << ")" << endl;
// no v.x no v.y
return 0;
}
I suggest you change the default constructor to
Vector() : x(0), y(0) {}
So it would have printed
v1 (0,0)
You should also change
Vector(float f1, float f2)
{
x=f1;
y=f2;
}
To
Vector(float f1, float f2) : x(f1), y(f2) {}
As it is a good habit to get into. This can save resources and CPU cycles when dealing with non POD types. For more information see Why should I prefer to use member initialization list?
the Vector v; line is a mistake. You are basically creating a new uninitialized vector instead of crating your own instance.
one correction would be:
int display()
{
cout << "(" << x << "," << y << ")" << endl;
return 0;
}
since x and y are member of this class