include <iostream>

include <deque>

include <string>

using namespace std;

int main() { deque<int> dq; string c; while (cin >> c) { if (c == "push") {int n; cin >> n; dq.push_back(n); cout << "ok\n";} else if (c == "pop") {cout << (dq.empty() ? "error\n" : to_string(dq.back()) + "\n"); if (!dq.empty()) dq.pop_back();} else if (c == "back") cout << (dq.empty() ? "error\n" : to_string(dq.back()) + "\n"); else if (c == "size") cout << dq.size() << "\n"; else if (c == "clear") {dq.clear(); cout << "ok\n";} else if (c == "exit") {cout << "bye\n"; break;} } return 0; }

kazim_255

import java.util.ArrayList; import java.util.Scanner;

public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); ArrayList<Integer> s = new ArrayList<Integer>(); int c = 0;

while(in.hasNext()) {
  String cmd = in.next();
  if("push".equals(cmd)) {
    s.add(in.nextInt()); c++;
    System.out.println("ok");
  }
  else
    if("pop".equals(cmd)) {
      if(c == 0) System.out.println("error");
      else System.out.println(s.remove(--c));
    }
    else
      if("back".equals(cmd)) {
        if(c == 0) System.out.println("error");
        else System.out.println(s.get(c-1));
      }
      else
        if("size".equals(cmd)) System.out.println(c);
        else
          if("clear".equals(cmd)) {
            s.clear(); c = 0;
            System.out.println("ok");
          }
          else { System.out.println("bye"); break; }
}

} }

Səhvlərdən qorunmuş stek

include <iostream>

include <deque>

include <string>