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-   -   Please explain some concepts about Pointer & Class & Array Pointer (http://www.go4expert.com/forums/explain-concepts-pointer-class-array-t20739/)

chaienbungbu 23Jan2010 02:55

Please explain some concepts about Pointer & Class & Array Pointer
 
I read this code section from a tutorial, but I cannot understand it thoroughly. It is about Pointer & Class Pointer & Array Pointer.

This is it:
Code:

// pointer to classes example
#include <iostream>
using namespace std;

class CRectangle {
        private:
                int width, height;
        public:
                // prototype
                void set_values (int,int);
                // method
                int area (void) {
                        return (width * height);
                }
};

// definion
void CRectangle :: set_values (int a, int b) {
        width = a;
        height = b;
}

void main () {
        CRectangle a, *b, *c;
        CRectangle * d = new CRectangle[2];
        //
        b = new CRectangle;
        c = &a;
        a.set_values(1,2);
        b -> set_values(3,4);
        d -> set_values(5,6);
        d[1].set_values(7,8);

        //
        cout << "a area: " << a.area() << endl;
        cout << "*b area: " << b -> area() << endl;
        cout << "*c area: " << c -> area() << endl;
        cout << "d[0] area: " << d[0].area() << endl;
        cout << "d[1] area: " << d[1].area() << endl;

        //
        delete[] d;
        delete b;       
}

I try to search google and understand some parts of this code. But when it contains many concepts (i.e. pointer, array, class) in the BOLD section, I cannot grasp the points. Many operators (*, ->, etc. ), and I failed to distinguish between them.

Please explain it for me, especially the section in BOLD.

BTW, I see the "new" operator is very different from java one, is it right?

Thanks for any help.


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