In C++, you can remove elements from the front of a queue using the pop() method. Here's an example:

#include <iostream>
#include <queue>

using namespace std;

int main() {
    queue<int> myQueue;
    
    myQueue.push(10);
    myQueue.push(20);
    myQueue.push(30);
    
    cout << "Size of queue before pop(): " << myQueue.size() << endl;
    
    myQueue.pop();  // Remove the first element (10) from the queue
    
    cout << "Size of queue after pop(): " << myQueue.size() << endl;
    
    return 0;
}

In the example above, we first create a queue called myQueue and add three integers to it using the push() method. We then use the size() method to print the number of elements in the queue before and after we remove the first element using the pop() method. The output of this program would be:

Size of queue before pop(): 3
Size of queue after pop(): 2

Note that the pop() method does not return the removed element. If you want to access the element before removing it, you can use the front() method to get a reference to the first element in the queue, and then use the pop() method to remove it.