C++ Programming - Objects and Classes - Discussion

In above example, immediate to classes declarations, objects I and B are also constructed in global space so that I.B.Display() will give value any of its member initialized to default i.e here y is 0.

Note 1: By keeping declaration in global space and try to create objects I and B inside main() then I.B.Display() will give any of its member value as Garbage.

Note 1: Inside main(), declare class as static and then create objects also, in this case I.B.Display() will give value any of its member initialized to default i.e here y is 0.


#include <iostream>
using namespace std;

class Bix
{
int x;
float y;
public:
void Display()
{
cout<< y << endl;
}
}B;

int main()
{
static class Bbb
{
int x;
float y;
public:
void Display()
{
cout<< y << endl;
}
}Bb;

Bix B1;
B.Display();
B1.Display();
Bb.Display();
return 0;
}

In this example, we are not calling function Function(). So, value of y & x are not changed that's why it's displaying 0.

The void function was not called only display is invoked ? then how initialized y=x=(x=4*4).

How you say y=x=(x=4*4) is equal to 1?

It's all about logical assignments.

y = x = (x = 4*4);

// Successful assignment " x=4*4 " returns.
// value 1 to x, in turn successful assignment " x = (...) ".
// returns value 1 to y, so y = 1; next.

y = --y * y; // --y is operated 1st so y = 0 now, then 0*0 = 0.

Yes, but this is not structure please explain in detail.

Why it's not 1?

Yes, Structure members are initialized to zero if not defined explicitly.

Structure members are initialized to zero if not defined explicitly.

Where it is declared global? please explain program in detail.

Object Declared as global.

So all global default value = 0.