Answers for "how to declare a stack in c++"

stack c++

stack<int> stk;
stk.push(5);
int ans = stk.top(5); // ans =5
stk.pop();//removes 5

stack c++

#include <bits/stdc++.h> 

stack<int> stk;
stk.push(5);
int ans = stk.top(5); // ans =5
stk.pop();//removes 5

stack in c++

#take input 2D vector

vector<vector<int> > v;
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
v[i].push_back(data);
}}