help for a oop newb please

[Vidus]

can someone help this is i need it to call individual update but it keeps calling base class update. here is the code

 #include <iostream>
#include <vector>
using namespace std;

class Shape
{
public:

Shape(){}
    
virtual void update(){cout << "Shape: Update\n";}
};


class SphereShape:public Shape
{
public:
float radius;

SphereShape():Shape(){radius = 10;}


virtual void update(){
     cout << "sphere update radius is: " << radius << endl;
    }
};



vector<Shape> shapes;



int main() {
	Shape testshape;
	shapes.push_back(testshape);
	SphereShape testsphere;
	shapes.push_back(testsphere);
	
	for(int i = 0;i < shapes.size();i++)
	  {
	  shapes[i].update();	
	  }
	
	return 0;
}

the output is
Shape: Update
Shape: Update

when in looking to have output
Shape: Update
sphere update radius is: 10

edit: changed to right code

[AbstractionAnon]

Two problems:

line 11: must be virtual

For polymorphism to work, you need to use pointers.

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#include <iostream> #include <vector> using namespace std; class Shape { public: Shape(){} virtual void update() { cout << "Shape: Update\n"; } }; class SphereShape:public Shape { public: float radius; SphereShape() { radius = 10; } void update() { cout << "sphere update radius is: " << radius << endl; } }; vector<Shape *> shapes; int main() { Shape testshape; shapes.push_back(&testshape); SphereShape testsphere; shapes.push_back(&testsphere); for (size_t i=0; i < shapes.size(); i++) { shapes[i]->update(); } system ("pause"); return 0; }

Shape: Update sphere update radius is: 10 Press any key to continue . . .

[Vidus]

yup that works thank you is there a way to do it without pointers?

[Zhuge]

Not really. When you do not use pointers, you "slice" the sphere object data out and leave only the shape data when you put it in the container.