array elements in a stack.

[aravind rao]

Hi

I am developing a program that uses Breadth First Search to map a grid(2d array) out. Breadth First Search involves storing nodes in a stack and then exploring these nodes based on Breadth or level. I know how to create a vector array which I shall use as a stack. I need to know how to store array elements in the stack using the

push_back()

method. This is what I have so far..

vector<int>stack; //stack initialization.
stack.push_back(array[1][1]) //store array element itself, not Value held in array!

The value stored is not the array element, but the value which happens to be some integer x.

Thanks for helping.

[NathanOliver]

if you want to store the address of that element in you vector than you can do

vector<int*> stack
stack.push_back(&(array[1][1]))

if you are trying to store the value of x and y values you can use a 2d vector like

vector< vector<int> > stack
vector<int> temp;
if (array[x][y] == something)
{
    temp.push_back(x);
    temp.push_back(y);
    stack.push_back(temp);
    temp.clear();
}

although this might not be the best way to do it.

[LordNemrod]

Why would you want to simulate a stack for a vector if there is already an implemented stack?!

#include <stack>
#include <iostream>
int main()
{
 std::stack<int>  st;
 st.push(1);
 st.push(3);
 std::cout << st.top() << std::endl; // outputs 3;
 st.pop();
 std::cout << st.top() << std::endl; //outputs1
}

[aravind rao]

Why would you want to simulate a stack for a vector if there is already an implemented stack?!

#include <stack>
#include <iostream>
int main()
{
 std::stack<int>  st;
 st.push(1);
 st.push(3);
 std::cout << st.top() << std::endl; // outputs 3;
 st.pop();
 std::cout << st.top() << std::endl; //outputs1
}

Well I looked into it, but for a Breadth First Search I need a FIFO(First In First Out) type stack. The one above is LIFO. So unless there is actually a FIFO stack, which I think only exists in a queue, I wont be using any stacks.

Thanks for replying.

[aravind rao]

if you want to store the address of that element in you vector than you can do

vector<int*> stack
stack.push_back(&(array[1][1]))

if you are trying to store the value of x and y values you can use a 2d vector like

vector< vector<int> > stack
vector<int> temp;
if (array[x][y] == something)
{
    temp.push_back(x);
    temp.push_back(y);
    stack.push_back(temp);
    temp.clear();
}

although this might not be the best way to do it.

Great post, both methods worked, although the pointer method is more efficient. I knew pointers were the answer, thanks for showing me how!

Thanks for replying.