Queue using two Stacks

PROBLEM :
Implement a Queue using 2 stacks s1 and s2 .

Input (To be used for Expected Output):

The first line of the input contains an integer 'T' denoting the number of test cases. Then T test cases follow.
First line of each test case contains an integer Q denoting the number of queries .
A Query Q is of 2 Types
(i) 1 x   (a query of this type means  pushing 'x' into the queue)
(ii) 2     (a query of this type means to pop element from queue and print the poped element)

The second line of each test case contains Q queries seperated by space.

Output:
The output for each test case will  be space separated integers having -1 if the queue is empty else the element poped out from the queue .
You are required to complete the two methods push which take one argument an integer 'x' to be pushed into the quee  and pop which returns a integer poped out from othe queue.

Constraints:
1<=T<=100
1<=Q<=100
1<=x<=100

Example:
Input
1
5
1 2 1 3 2 1 4 2

Output
2 3

Explanation:

In the first test case for query
1 2    the quee will be {2}
1 3    the queue will be {2 3}
2       poped element will be 2 the queue will be {3}
1 4    the queue will be {3 4}
2       poped element will be 3

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SIMPLE c++ IMPLEMENTATION :
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/* The structure of the class is
class StackQueue{
private:
    // These are STL stacks ( http://goo.gl/LxlRZQ )
    stack<int> s1;
    stack<int> s2;
public:
    void push(int);
    int pop();
}; */

/* The method push to push element into the queue */
void StackQueue :: push(int x)
 {
    s1.push(x) ;  
 }

/*The method pop which return the element poped out of the queue*/
int StackQueue :: pop()
{
    if(s1.empty())
        return -1 ;

    while(!s1.empty())
    {
        s2.push(s1.top()) ;
        s1.pop() ;
    }
 
    int temp ;
    temp=s2.top();
    s2.pop() ;
 
    while(!s2.empty())
    {
        s1.push(s2.top()) ;
        s2.pop() ;
    }
    return temp ;
}

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SIMPLE c++ IMPLEMENTATION :(Using one stack & recurtion)
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credits : https://www.facebook.com/golupatidar.patidar.9

/* The structure of the class is
class StackQueue{
private:
    // These are STL stacks ( http://goo.gl/LxlRZQ )
    stack<int> s1;
    stack<int> s2;
public:
    void push(int);
    int pop();
}; */

/* The method push to push element into the queue */
/* The method push to push element into the queue */
int Pop();
void StackQueue :: push(int x)
 {
    s1.push(x) ;  
 }

/*The method pop which return the element poped out of the queue*/
int StackQueue :: pop()
{
    int n;
 
    if(s1.empty())
        return -1;
   
    n=s1.top();
    if(s1.size()==1)
    {
        s1.pop();
        return n;
    }
    s1.pop();
    int res=pop();
    s1.push(n);
 
   return res;
}

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