PracticeCode/Sort_Stack.cpp at master · zakir8251/PracticeCode · GitHub

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#include <iostream>
#include <stack>
using namespace std;

void insert_in_sorted_stack(stack<int>& S, int top){

  //Base case TBD
  if(S.empty()) {S.push(top); return;}

  if(top<S.top()) S.push(top);
  else{
    int curr_top = S.top();
    S.pop();
    insert_in_sorted_stack(S, top);
    S.push(curr_top);
  }
}

void sort_stack(stack<int>& S){

  if(S.size() < 2) return;

  int top = S.top();
  S.pop();
  sort_stack(S);

  insert_in_sorted_stack(S, top);

  return;
}

void print_stack(stack<int> S){
  if(S.empty()) return;
  cout<<S.top()<<endl;
  int top = S.top();
  S.pop();
  print_stack(S);
  S.push(top);

}

/*
  The goal here is to sort the given stack using recursion
*/
int main() {

  stack<int> S;

  S.push(10);
  S.push(12);
  S.push(1);
  S.push(14);
  S.push(4);
  S.push(44);

  print_stack(S);
  cout<<endl;
  sort_stack(S);
  print_stack(S);

  return 0;
}
/* Prints:-
44
4
14
1
12
10

1
4
10
12
14
44
*/