The document provides an overview of data structures in C++, focusing on vectors, stacks, and queues. It includes syntax for declaring and utilizing these structures, key member functions, and examples of their usage. Additionally, it presents a homework assignment to determine the appropriate data structure for different problems.

1. Lesson #6 - Data Structures
By: Alfonso Torres

2. Lesson Overview
● Vectors
● Stacks
● Queues

3. Vectors

4. What is a Vector?
● Vector - collects a sequence of values, just like an array does, but its size can
change.
● Before using a vector there is one important thing to take in mind. You need to
use the Vector Library. On the top of your program you need to call the library
#include <vector>, this syntax will let your program know that you can use
vectors and their member functions.
● Vector Syntax
○ vector<type> vectorName; //example
○ vector<double> values; //empty vector of type double
○ vector<double> values(10); //vector with a size of 10
○ vector<double> values = {32,22.5,6,11,33}; //specifying initial values
○ vector[0] = 5; //updating value in vector (similar to arrays)

5. Vector Member Function
Examples
● In the code snippet there is an example of a
few vector member functions. These are the
functions we used: Vector Example
○ size(); //returns size of vector
○ push_back(x); //adds element at the end
○ pop_back(); //removes last element
● This is the syntax you need to write to use
the member functions:
○ vectorName.memeberFunction();

6. Practice - Vectors
● Follow the commands given to you in the comments. At the end of your
program there will be a loop to check your work and see if you followed the
commands correctly: Practice - Vectors
● Things to think about:
○ What does does the vector member function push_back() do?
○ Will this code work?
■ vec.pop_back(11);
○ Name some differences between arrays.

7. Stacks & Queues

8. What are Stacks and Queues?
● Stack - is a container of elements that follows “last in, first out”(LIFO) retrieval
method. The stack lets you insert and remove elements at one end only.
○ To use a stack container you will need to call the #include <stack> library
on top of your main program.
○ stack<dataType> stackName; //Example
○ stack<string> myStack; //Creating a stack
● Queue - is a container of elements that follows the “first in, first out”(FIFO)
retrieval method. A queue lets you add elements at one end (the back or tail)
and remove elements at the other end (the front or head).
○ To use a queue container you will need to call the #include <queue>
library on top of your main program.
○ queue<dataType> queueName; //Example
○ queue<string> myQueue; //Creating a queue

9. Stack Member Function
Examples
● In the code snippet there is an example
of stack member functions. These are
the functions we used: Stack Example
○ size(); //returns size of vector
○ push(x); //adds element at the top
○ pop(); //removes element at the top
○ top(); //returns the top element
● This is the syntax you need to use to use
the member functions:
○ stackName.memeberFunction();

10. Queue Member Function
Examples
● In the code snippet there is an example
of queue member functions. These are
the functions we used: Queue Example
○ size(); //returns size of vector
○ push(x); //adds element at the end
○ pop(); //removes first element
○ front(); //returns first element
● This is the syntax you need to use to use
the member functions:
○ queueName.memeberFunction();

11. Homework - The Right Fit
● In this homework we will be finding the right data structure to use for each
problem in our program. We will be able to choose from arrays, vectors,
stacks, and queues : Homework - The Right Fit
● Things to think about:
○ What does FIFO stand for?
○ What does LIFO stand for?
○ Pretend you wanted to keep track of an unknown number names, what
data structure would you use? Explain your answer.

12. Lesson Summary
● Vector - collects a sequence of values, just like an array does, but its size can
change.
● Before using a vector there is one important thing to take in mind. You need to
use the Vector Library. On the top of your program you need to call the library
#include <vector>, this syntax will let your program know that you can use
vectors and their member functions.
○ size(); //returns size of vector
○ push_back(x); //adds element at the end
○ pop_back(); //removes last element
● Stack - is a container of elements that follows “last in, first out”(LIFO) retrieval
method. The stack lets you insert and remove elements at one end only.
○ size(); //returns size of vector
○ push(x); //adds element at the top
○ pop(); //removes element at the top
○ top(); //returns the top element

13. Lesson Summary
● Queue - is a container of elements that follows the “first in, first out”(FIFO)
retrieval method. A queue lets you add elements at one end (the back or tail)
and remove elements at the other end (the front or head).
○ size(); //returns size of vector
○ push(x); //adds element at the end
○ pop(); //removes first element
○ front(); //returns first element

14. Solutions
● Practice - Vectors - Solution
● Homework - The Right Fit - Solution

15. References
● Big C++: Late Objects 3rd Edition
● C++ STL Tutorial - Vectors
● cpluplus - Vectors

16. Thank You!