Implementing queue

[Sharan123]

I have made a struct Queue and now i want an object for Queue but it says it doesn't not have storing capabilities , It works when i try to make it in function it accesses s front and rear

  struct Queue
{
	int items[length];
	int front ,rear;
};
Queue q;
q.front=-1;//does not work why??
void Enque(int x)
{
	q.front=1;//does work why?? 

[Amil Patel]

I'm not great in programming but try creating a constructor for q.front=-1 for example

struct Queue
{
int items[length];
int front, rear;
    Queue
    {
         Queue q;
         q.front=-1;
    }
};

[Sharan123]

Yes , it does work in constructor never came into my mind to apply constructor, but still why doesn't the first thread method work ? o_0

[cire]

You can't put executable code outside of a function.

int some_func()
{
    // do some stuff.
}

std::swap(x,y);

void other_func()
{
    // do something with x and y
}

How would you expect this code to behave? When would the swap function be called?

[Sharan123]

When would the swap function be called?

Swap function will not be called.
Sorry but i still don't understand why can't i make global instance of Queue can you ignore Enguue() function and how will be it possible to make an object of Queue and assign -1 to its front member?

You can't put executable code outside of a function.

But Queue isn't a function it's a structure.

[cire]

Sharan123 wrote:

Swap function will not be called.

The swap function there will result in a syntax error, just as your assignment did in the OP.

Sharan123 wrote:

Sorry but i still don't understand why can't i make global instance of Queue can you ignore Enguue() function and how will be it possible to make an object of Queue and assign -1 to its front member?

You can make a global instance of Queue. You cannot assign values to that object outside of a function unless it is part of the initialization of that object.

If you insist on not defining an appropriate constructor:

const unsigned length = 256;

struct Queue
{
    int items[length];
    int front, rear;
};

Queue q = { {}, -1 }; // initialization  

cire wrote:

You can't put executable code outside of a function.

Sharan123 wrote:

But Queue isn't a function it's a structure.

Yes, that's what I said. You can't put executable code outside of a function.