QT enum array

[angarali06]

Hi everybody,

How can I declare an array of shape in QPainter?

In the header file, I have an enumerated shape. It works fine without making array. But now I want to have an array of size 10 of this enumerated shape. I could not successfully convert the shape to an array of size 10. Please help..

Here are my code pieces:

my header file

enum Shape {Kare, Hexa, Rect};
void setShape(Shape shape[10]);
Shape shape[10];

enum Shape {Kare, Hexa, Rect};
void setShape(Shape shape[10]);
Shape shape[10];

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my cpp file

void RenderArea1::setShape(Shape shape[10])
 {  
     for (int kat = 0; kat < 10; kat += 1) {
	 this->shape[kat] = shape[kat];
     update();
	 }
 }
 
for (int kat = 0; kat < 10; kat += 1) {
 
	switch (shape[kat]) {
 
                 case Kare:
                           ....
                 case Hexa:
                           ....
                 case Rect:
                           ....
              }
}
 
RenderArea1::Shape shape[Window::kat] = renderArea1->Kare;
renderArea1->setShape(shape[Window::kat]);
renderArea1->update();

void RenderArea1::setShape(Shape shape[10])
 {  
     for (int kat = 0; kat < 10; kat += 1) {
	 this->shape[kat] = shape[kat];
     update();
	 }
 }

for (int kat = 0; kat < 10; kat += 1) {

	switch (shape[kat]) {

                 case Kare:
                           ....
                 case Hexa:
                           ....
                 case Rect:
                           ....
              }
}

RenderArea1::Shape shape[Window::kat] = renderArea1->Kare;
renderArea1->setShape(shape[Window::kat]);
renderArea1->update();

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Thanks in advance..

[wysota]

I could not successfully convert the shape to an array of size 10.

What does it mean exactly? It doesn't compile? What error do you get?

[stampede]

Hard-coded stuff is bad. Imagine that at some point you'd like to use 20 shapes instead of 10 - in your case that means replacing the values in every place in your code. This is bug-prone, because you can forget about something. Simple improvement could be to use #define for number of shapes:

#define N_SHAPES 10
...
enum Shape {Kare, Hexa, Rect};
void setShape(Shape shape[N_SHAPES]);
Shape shape[N_SHAPES];
...
for (int kat = 0; kat < N_SHAPES; kat += 1) {
	 this->shape[kat] = shape[kat];
     update();
	 }
//... and so on

#define N_SHAPES 10
...
enum Shape {Kare, Hexa, Rect};
void setShape(Shape shape[N_SHAPES]);
Shape shape[N_SHAPES];
...
for (int kat = 0; kat < N_SHAPES; kat += 1) {
	 this->shape[kat] = shape[kat];
     update();
	 }
//... and so on

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Furthermore, I'd switch to one of Qt containers instead of C-styled arrays - for example, take a look at QList.

[angarali06]

thanks stampede but I still got these errors:

for line 22
expected constant expression
cannot allocate an array of constant size 0
error C2440: 'initializing' : cannot convert from 'RenderArea1::Shape' to 'RenderArea1::Shape []'
There are no conversions to array types, although there are conversions to references or pointers to arrays
for line 23
'RenderArea1::setShape' : cannot convert parameter 1 from 'RenderArea1::Shape' to 'RenderArea1::Shape []'
Conversion from integral type to pointer type requires reinterpret_cast, C-style cast or function-style cast

[stampede]

RenderArea1::Shape shape[Window::kat] = renderArea1->Kare;

RenderArea1::Shape shape[Window::kat] = renderArea1->Kare;

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What do you mean by this line ? Window::kat is some kind of enum value ? This declares an array of Shapes, with number of elements equal to Window::kat value, which seems to be 0 according to compiler message. Next you want to assign a single value for the array, you can't do that because there are different types.

renderArea1->setShape(shape[Window::kat]);

setShape method expects an array, and you are giving it only one value ( shape[Window::kat] is probably the same as shape[0], assuming that Window::kat==0 ). Probably you mean

renderArea1->setShape(shape);

renderArea1->setShape(shape);

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but there is still first error to fix.
For me this looks like a basic C/C++ issues, not really related to Qt.