queue c++

#include<iostream>
#include<queue>
using namespace std;
void showq(queue <int> gq)
{
    queue <int> g = gq;
    while (!g.empty())
    {
        cout << ' ' << g.front();
        g.pop();
    }
    cout << '\n';
}
int main()
{
    queue<int> gquiz;
    gquiz.push(10);
    gquiz.push(20);
    gquiz.push(30);
 	cout << "Front Element: ";
    cout << gquiz.front();
  
    cout << "\nThe queue gquiz is:";
    showq(gquiz);
}

// CPP program to illustrate 
// Implementation of push() function 
#include <iostream> 
#include <queue> 
using namespace std; 
  
int main() 
{ 
    // Empty Queue 
    queue<int> myqueue; 
    myqueue.push(0); 
    myqueue.push(1); 
    myqueue.push(2); 
  
    // Printing content of queue 
    while (!myqueue.empty()) { 
        cout << ' ' << myqueue.front(); 
        myqueue.pop(); 
    } 
} 

// CPP code to illustrate  
// Queue in Standard Template Library (STL) 
#include <iostream> 
#include <queue> 
  
using namespace std; 
  
void showq(queue <int> gq) 
{ 
    queue <int> g = gq; 
    while (!g.empty()) 
    { 
        cout << '\t' << g.front(); 
        g.pop(); 
    } 
    cout << '\n'; 
} 
  
int main() 
{ 
    queue <int> gquiz; 
    gquiz.push(10); 
    gquiz.push(20); 
    gquiz.push(30); 
  
    cout << "The queue gquiz is : "; 
    showq(gquiz); 
  
    cout << "\ngquiz.size() : " << gquiz.size(); 
    cout << "\ngquiz.front() : " << gquiz.front(); 
    cout << "\ngquiz.back() : " << gquiz.back(); 
  
    cout << "\ngquiz.pop() : "; 
    gquiz.pop(); 
    showq(gquiz); 
  
    return 0; 
}