List of Stacks in C++ STL
Last Updated :
15 Jul, 2025
Prerequisite: List, Stack
Lists are sequence containers that allow non-contiguous memory allocation. As compared to vector, list has slow traversal, but once a position has been found, insertion and deletion are quick.
Syntax:
list <Type> name_of_list;
Stack are a type of container adaptor with LIFO(Last In First Out) type of work, where a new element is added at one end and (top) an element is removed from that end only.
Syntax:
stack <Type> name_of_stack;
List of Stacks are a type of container which have a series of stacks, this is a two-dimensional container where N rows of list and M column of stacks, size of both dimension is non-fixed. which can be traversed and accessed using iterators.
Syntax:
list <stack <Type> > name_of_container(size);
where size is optional
Example:
list <stack <int> > ls(10);
size of list of stacks is 10
Insertion: Insertion in the list of the stack is done using the push() function.
Example:
C++
// Loop to push element
// into a stack
for
i in[0, n]
{
s.push(i)
}
// Push Stack into the list
ls.push_back(s);
Traversal: Traversal in a list of the stack is performed using iterators.
C++
// Loop to iterate over list
for (iterator it = ls.begin();
it != ls.end(); it++) {
// Stack of the List
stack<int>
st = *it;
while (!st.empty()) {
cout << st.top();
st.pop();
}
}
Above code traverses list<int> ls at each index using starting iterators ls.begin() and ending iterator ls.end(). For accessing the element it uses (*it) as stack are pointers pointing to elements in list <stack <int> > ls.
Below is the program to illustrate the insertion and traversal in lists of stacks:
C++
// C++ program for implementation
// of the lists of stack
#include <bits/stdc++.h>
using namespace std;
// Function for printing the
// elements in a list
void showlist(list<stack<int> > ls)
{
// Traverse the list and
// print row wise stack
for (list<stack<int> >::iterator it1
= ls.begin();
it1 != ls.end(); ++it1) {
// Copy rows in stack
stack<int> it2 = *it1;
// Print stack elements while
// it is not empty
while (!it2.empty()) {
cout << it2.top() << " ";
it2.pop();
}
cout << endl;
}
}
// Driver Code
int main()
{
// List of stacks
list<stack<int> > ls;
// Insert rows in list
for (int i = 0; i < 10; ++i) {
// Insert element in
// stack as column
stack<int> s;
for (int j = i; j < 10; j++) {
s.push(j);
}
ls.push_back(s);
}
cout << "List of stack is : \n";
showlist(ls);
return 0;
}
Output:
List of stack is :
9 8 7 6 5 4 3 2 1 0
9 8 7 6 5 4 3 2 1
9 8 7 6 5 4 3 2
9 8 7 6 5 4 3
9 8 7 6 5 4
9 8 7 6 5
9 8 7 6
9 8 7
9 8
9
