1. In the folder src/bin, create a file called vecdeque.rs.
2. Add the following code, and run it with cargo run --bin vecdeque:

1   use std::collections::VecDeque;
2 
3   fn main() {
4     // A VecDeque is best thought of as a
5     // First-In-First-Out (FIFO) queue
6 
7     // Usually, you will use it to push_back data
8     // and then remove it again with pop_front
9     let mut orders = VecDeque::new();
10    println!("A guest ordered oysters!");
11    orders.push_back("oysters");
12 
13    println!("A guest ordered fish and chips!");
14    orders.push_back("fish and chips");
15 
16    let prepared = orders.pop_front();
17    if let Some(prepared) = prepared {
18      println!("{} are ready", prepared);
19    }
20 
21    println!("A guest ordered mozarella sticks!");
22    orders.push_back("mozarella sticks");
23 
24    let prepared = orders.pop_front();
25    if let Some(prepared) = prepared {
26      println!("{} are ready", prepared);
27    }
28 
29    println!("A guest ordered onion rings!");
30    orders.push_back("onion rings");
31 
32    let prepared = orders.pop_front();
33    if let Some(prepared) = prepared {
34      println!("{} are ready", prepared);
35    }
36 
37    let prepared = orders.pop_front();
38    if let Some(prepared) = prepared {
39      println!("{} are ready", prepared);
40    }
41 
42    // You can freely switch your pushing
43    // from front to back and vice versa
44    let mut sentence = VecDeque::new();
45    sentence.push_back("a");
46    sentence.push_front("had");
47    sentence.push_back("little");
48    sentence.push_front("Mary");
49    sentence.push_back("Lamb");
50    println!("sentence: {:?}", sentence);
51 
52    // The same applies to popping data
53    sentence.pop_front();
54    sentence.push_front("Jimmy");
55    sentence.pop_back();
56    sentence.push_back("Cat");
57    println!("sentence: {:?}", sentence);
58 
59 
60    // The rest of the VecDeque's methods are
61    // pretty much the same as the vector's
62    // However, the VecDeque has additional options
63    // when swap removing!
64    let mut some_queue = VecDeque::with_capacity(5);
65    some_queue.push_back("A");
66    some_queue.push_back("B");
67    some_queue.push_back("C");
68    some_queue.push_back("D");
69    some_queue.push_back("E");
70    println!("some_queue: {:?}", some_queue);
71 
72    // This is the same as Vec's swap_remove
73    some_queue.swap_remove_back(2);
74    println!("some_quere after swap_remove_back: {:?}",
        some_queue);
75 
76    // This is the nearly the same, but swaps the removed
77    // element with the first one instead of the last one
78    some_queue.swap_remove_front(2);
79    println!("some_quere after swap_remove_front: {:?}",
        some_queue);
80    }