printing elements of stack

[arnuld]

WANT: print stack elements
PROBLEM: No way to print

This is the code from section 12.1.2 of Nicolai's 2nd edition:

#include <iostream>
#include <stack>

int main()
{
std::stack<int> st;

st.push(10);
st.push(11);
st.push(12);

std::cout << ":STACK:" << std::endl;
std::cout << "size = " << st.size() << std::endl;

while(!st.empty())
{
std::cout << st.top() << "\n";
st.pop();
}

std::cout << std::endl;


return 0;
}



It prints the elements but makes empty too. Is there no way to print
stack elements without pop()-ing them out ?

[Christian Gollwitzer]

Am 17.09.14 07:38, schrieb arnuld:

> WANT: print stack elements
> PROBLEM: No way to print

Stacks do not provide the facility to iterate over the elements. But you
can use a std::vector instead of a stack easily:

> This is the code from section 12.1.2 of Nicolai's 2nd edition:

Adapted:

#include <iostream>
#include <vector>

int main()
{
std::vector<int> st;

st.push_back(10);
st.push_back(11);
st.push_back(12);

std::cout << ":STACK:" << std::endl;
std::cout << "size = " << st.size() << std::endl;

std::cout<<"Stack content: "<<std::endl;
// print non-destructively
for (auto &x: st) {
std::cout<<x<<std::endl;
}

std::cout<<"Popping down stack:"<<std::endl;
// now popdown stack
while(!st.empty())
{
std::cout << st.back() << "\n";
st.pop_back();

}

std::cout << std::endl;


return 0;
}

Christian

[Jorgen Grahn]

On Wed, 2014-09-17, Christian Gollwitzer wrote:
> Am 17.09.14 07:38, schrieb arnuld:
>> WANT: print stack elements
>> PROBLEM: No way to print
>
> Stacks do not provide the facility to iterate over the elements. But you
> can use a std::vector instead of a stack easily:
>
>> This is the code from section 12.1.2 of Nicolai's 2nd edition:
>
> Adapted:
>
> #include <iostream>
> #include <vector>
>
> int main()
> {
> std::vector<int> st;

That's not a stack in the OP's sense -- but perhaps that was your
point?

/Jorgen

--
// Jorgen Grahn <grahn@ Oo o. . .
\X/ snipabacken.se> O o .

[Victor Bazarov]

Stack is not a container over which you can iterate without altering it.
In that sense it's similar to streams.

V
--
I do not respond to top-posted replies, please don't ask

[Charles J. Daniels]

You could pop a stack and push the elements onto a new stack after printing them. They'd be "upside-down" but when you're done you could pop them off back onto the original stack.

[Rick C. Hodgin]

On Wednesday, September 17, 2014 1:38:34 AM UTC-4, arnuld wrote:
> WANT: print stack elements
> PROBLEM: No way to print
>

> Is there no way to print stack elements without pop()-ing them out ?

The stack stores memory somewhere. Generate the assembly and determine
how it's being accessed through the standard C++ mechanisms. You can
then iterate through the same memory manually using a pointer of some
kind.

In the alternative, create your own stack system using Christian's
suggestion.

Best regards,
Rick C. Hodgin

[Scott Neugroschl]

Alternatively, derive from std::stack<> using private inheritance.
The underlying container in std::stack is protected.

[Rosario193]

On 17 Sep 2014 05:38:11 GMT, arnuld <sun...@invalid.address> wrote:

>WANT: print stack elements
>PROBLEM: No way to print

it is possible to print using onhother stack...

#include <iostream>
#include <stack>

int main(void)
{ std::stack<int> st, v;
int r;

st.push(10);
st.push(11);
st.push(12);

std::cout << ":STACK:" << std::endl;
std::cout << "size = " << st.size() << std::endl;

while(!st.empty())

{//r=st.pop();
r=st.top(); st.pop();
std::cout << r << "\n";
v.push(r);
}
while(!v.empty())
{//r=v.pop();
r=v.top(); v.pop();
st.push(r);

[Christian Gollwitzer]

Am 17.09.14 12:34, schrieb Jorgen Grahn:

> On Wed, 2014-09-17, Christian Gollwitzer wrote:
>> Stacks do not provide the facility to iterate over the elements. But you
>> can use a std::vector instead of a stack easily:
>>

>> std::vector<int> st;
>
> That's not a stack in the OP's sense -- but perhaps that was your
> point?

Yes, it was, you even quoted my statement saying so:)

Christian

[Jorgen Grahn]

Oops. Indeed I did :-)