/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 21 1\. Suppose that you have the fo... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 10: Problem 21

1\. Suppose that you have the following C++ code: vector myList(5); unsigned int length; myList[0] = 3; for (int i = 1; i < 4; i++) myList[i] = 2 * myList[i - 1] - 5; myList.push_back(46); myList.push_back(57); myList.push_back(35); a. Write a C++ statement that outputs the first and the last elements of myList. (Do not use the array subscripting operator or the index of the elements.) b. Write a C++ statement that stores the size of myList into length. c. Write a for loop that outputs the elements of myList.

Short Answer

Expert verified
Use `myList.front()` and `myList.back()` to access first and last elements. Use `myList.size()` for length. Output elements with a range-based for loop.

Step by step solution

01

Initialize vector and populate

The code initializes a vector `myList` with 5 integers, setting the initial elements to zero. Then `myList[0]` is set to 3. A loop populates `myList[1]` to `myList[3]` using the formula `2 * myList[i - 1] - 5`. Then elements 46, 57, and 35 are pushed to the end of the vector.
02

Determine first and last elements without subscripting

To output the first and last elements of the vector `myList` without using subscripting, we utilize iterators. In C++, you can do this by using `myList.front()` to access the first element and `myList.back()` to access the last element.
03

Store size of vector into length

To store the size of `myList` into `length`, the method `myList.size()` is used. This gives the total number of elements in the vector and can be stored directly into `length`.
04

Write a for loop to output elements

To output each element in `myList`, a for loop iterating over the vector using an iterator is used. In C++, this can be accomplished either with a range-based for loop or an iterator from begin to end. The range-based loop looks like: `for(auto elem : myList) { cout << elem << " "; }`.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Vectors in C++
Vectors in C++ are a type of sequence container representing arrays that can grow dynamically. They are part of the Standard Template Library (STL) and provide several advantages over traditional arrays:
  • **Dynamic Sizing:** Unlike arrays, vectors can change in size, making them flexible and convenient when working with data collections that vary. You do not have to specify the size upfront.
  • **Access Elements:** You can access elements using the `at()` method or directly through subscripting (e.g., `vec[i]`). However, STL provides additional methods such as `front()` and `back()`.
  • **Memory Management:** Vectors manage the storage automatically, growing as necessary by allocating new memory and deallocating old memory as needed.
Understanding how vectors work is crucial for effective C++ programming because they combine the clarity of arrays with the dynamic properties of linked lists, giving you the best of both worlds.
Iterators in C++
Iterators in C++ are objects that facilitate the traversal and manipulation of elements in containers like vectors. They perform a role akin to pointers in arrays, allowing programmers to navigate through the data.
  • **Types of Iterators:** Iterators can be constant, mutable, or reverse. The type used depends on the needed operations and whether modification of elements is required.
  • **Using Iterators:** Use `begin()` and `end()` to get iterators pointing to the start and just past the last element of the container. For instance, iterating through a vector can be achieved with a `for` loop using these iterators.
  • **Advantages:** Iterators help in abstracting container details, ensuring code compatibility across different container types by using the same iterator interface.
Iterators are essential in C++ as they provide a standard way of operating on containers, leading to more readable and efficient code.
Range-Based For Loop
The range-based for loop in C++ is a simplified looping construct for iterating over elements in a container like vectors. Introduced in C++11, it enhances readability and reduces the likelihood of errors in your code.
  • **Syntax:** The syntax is `for (auto &element : container)`, where `element` takes on each successive value from the container.
  • **Benefits:** It requires fewer lines of code compared to traditional loops and minimizes the risks associated with incorrect indexing.
  • **Use Cases:** Best for situations where you need to access elements without modifying them, ensuring easy iteration through all elements of a container.
The range-based for loop simplifies iteration and makes code cleaner and easier to understand.
C++ STL Methods
C++ Standard Template Library (STL) provides a range of methods that make handling data structures like vectors more intuitive and less error-prone.
  • **Common Methods:** Methods such as `push_back()` add elements to the end of a vector, `size()` returns the number of elements, `clear()` removes all elements, and `insert()` allows inserting elements at any position.
  • **Convenience:** These methods encapsulate common operations, saving time and effort by eliminating the need to manage memory or create complex algorithms from scratch.
  • **Reliability:** Using STL methods ensures that operations are bound by the same rules, providing consistency across an application.
Mastering STL methods provides a solid foundation for any C++ programmer, enabling the creation of efficient and high-quality applications.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Sort the following list using the bubble sort algorithm as discussed in this chapter. Show the list after each iteration of the outer for loop. 26,45,17,65,33,55,12,18

Consider the following list: 28,18,21,10,25,30,12,71,32,58,15 This list is to be sorted using the insertion sort algorithm as described in this chapter. Show the resulting list after six passes of the sorting phase -that is, after six iterations of the for loop.

Consider the following list: 7,28,31,40,5,20 The first four keys are in order. To move 5 to its proper position using the insertion sort as described in this chapter, exactly how many key comparisons are executed?

a. It was remarked in this chapter that the performance of bubble sort can be improved if we stop the sorting process as soon as we find that in an iteration, no swapping of elements takes place. Write a function that implements bubble sort algorithm using this fact. b. Using the algorithm that you designed in part (a), find the number of iterations that are needed to sort the list: 65,14,52,43,75,25,80,90,95

a. Write a C++ statement that declares secretList to be a vector object to store integers. (Do not specify the size of secretList.) b. Write C++ statements to store the following values, in the order given, into secretList: 56, 28, 32, 96, 75 c. Write a for loop that outputs the contents of secretList. (Use the expression secretList.size() to determine the size of secretList.)
See all solutions

Recommended explanations on Computer Science Textbooks

Computer Systems

Read Explanation

Computer Organisation and Architecture

Read Explanation

Databases

Read Explanation

Algorithms in Computer Science

Read Explanation

Cloud Services

Read Explanation

Big Data

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.