Working with Deque Indexes

The provided C++ code uses the Standard Template Library (STL) `deque` (double-ended queue) to collect positive numbers from the user until the user inputs -1, which signals they want to quit. Here's a breakdown of the code: 1. **Imports**: It includes the `<iostream>` header for input and output and `<deque>` for using the `deque` container. 2. **Main Function**: The `main()` function starts execution. 3. **Deque Initialization**: A `deque` named `numbers` is initialized to hold 5 integers. However, since the size is fixed, further elements will need to overwrite existing ones if more than 5 inputs are provided. 4. **Iterator Declaration**: An iterator `it` for the `deque` is declared to traverse through its elements. 5. **Input Loop**: A loop begins that allows the user to enter positive numbers. The user is prompted to enter a positive number, and if they enter -1, the loop breaks, terminating input collection. 6. **Storing Input**: The entered number is stored at the current position pointed to by the iterator `it`. After each input, it outputs the current size of the deque, which remains constant at 5. 7. **End of Program**: Once -1 is entered, the loop exits and the program ends. This code serves as a simple way to gather user input while demonstrating the use of STL containers and iterators in C++. Note that if more than 5 numbers are input, only the first 5 will be stored, as the `deque` is initialized with a fixed size.