Vectors

Learn how to use C++ vectors, a great way to keep your data organized.

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Key Concepts

Review core concepts you need to learn to master this subject

Vectors

Vector Type

.push_back() & .pop_back()

.size() Function

Index

Vectors

#include <iostream>
#include <vector>

int main() {
  
  std::vector<int> grades(3);
  
  grades[0] = 90;
  grades[1] = 86;
  grades[2] = 98;
  
}

In C++, a vector is a dynamic list of items, that can shrink and grow in size. It is created using std::vector<type> name; and it can only store values of the same type.

To use vectors, it is necessary to #include the vector library.

Vectors

Lesson 1 of 1

1
Introduction to Vectors
To do just about anything of interest in a program, we need a group of data to work with. For example, our program might need: - A list of Twitter’s trending tags - A set of payment options for a…
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2
Creating a Vector
The std::vector lives in the header. So first, we need to add this line of code at the top of the program: #include For review, #include is a preprocessor directive that tells the compiler t…
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3
Initializing a Vector
Now we know how to create a vector, we can also initialize a vector, giving it values, as we are creating it in the same line. For example, instead of just creating a double vector named location:…
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4
Index
Now that we have a vector, how do we access an individual element? This is where index comes into play. An index refers to an element’s position within an ordered list. Vectors are 0-indexed, me…
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5
Adding and Removing Elements
Often, we start with a vector that’s either empty or a certain length. As we read or compute data we want, we can grow the vector as needed. ##### .push_back() ##### To add a new element to the “…
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6
.size()
not only stores the elements; it also stores the size of the vector: The .size() function returns the number of elemen…
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7
Operations
So what happens when you want to change each of the values within a vector? You can use a for loop! For example, suppose we have an int vector that looks like this: ![1](https://content.codecade…
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8
Review
Congratulations! You have learned about how to store groups of data into vectors in C++. 🙌 Here are some of the things that we learned: - Vectors are a sequence of elements that you can access by…
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