C++ STL Set 4 (stack).cpp

//{ Driver Code Starts
#include <bits/stdc++.h>
using namespace std;

void push(stack<int> &s, int x);
int pop(stack<int> &s);

int getSize(stack<int> &s);

int getTop(stack<int> &s);
int main()
{
    // your code goes here
    int t;
    cin >> t;
    while (t--)
    {
        stack<int> s;
        int q;
        cin >> q;
        while (q--)
        {
            char c;
            cin >> c;
            if (c == 'a')
            {
                int x;
                cin >> x;
                push(s, x);
            }
            if (c == 'b')
            {
                cout << pop(s) << " ";
            }
            if (c == 'c')
            {
                cout << getSize(s) << " ";
            }
            if (c == 'd')
            {
                cout << getTop(s) << " ";
            }
        }
        cout << endl;
    }
    return 0;
}
// } Driver Code Ends

/*You are required to complete below methods*/

/*the function pushes an element
x into the stack s */
void push(stack<int> &s, int x)
{
    s.push(x);
}

/*pops the top element of the
stack and returns it */
int pop(stack<int> &s)
{
    if (s.size() > 0)
    {
        int res = s.top();
        s.pop();
        return res;
    }
    return -1;
}

/*returns the size of the stack */
int getSize(stack<int> &s)
{
    return s.size();
}

/*returns the top element
of the stack */
int getTop(stack<int> &s)
{
    if (s.size() > 0)
    {
        return s.top();
    }
    return -1;
}