Vector

In the world of programming, a vector is a dynamic array that can grow or shrink in size at runtime. It is one of the most commonly used data structures in C++ and provides several important features.

The vector in C++ is defined in the <vector> header and is part of the Standard Template Library (STL). It is implemented as a template class, allowing us to create vectors of different types, such as int, double, or even custom classes.

Creating a Vector

To create a vector, we need to include the <vector> header and declare a vector object with the desired type, followed by the name.

Here's an example of creating a vector of integers:

1#include <iostream>
2#include <vector>
3
4int main() {
5  // Declare a vector of integers
6  std::vector<int> numbers;
7
8  // ...
9}

Adding Elements to a Vector

We can add elements to a vector using the push_back() function, which adds the element to the end of the vector. The vector automatically grows in size as we add elements.

Here's an example of adding elements to a vector:

1// Add elements to the vector
2numbers.push_back(10);
3numbers.push_back(20);
4numbers.push_back(30);

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#include <iostream>

#include <vector>

​

int main() {

  // Declare a vector of integers

  std::vector<int> numbers;

​

  // Add elements to the vector

  numbers.push_back(10);

  numbers.push_back(20);

  numbers.push_back(30);

​

  // Print the elements

  std::cout << "Vector elements: ";

  for (int i = 0; i < numbers.size(); i++) {

    std::cout << numbers[i] << " ";

  }

  std::cout << std::endl;

​

  return 0;

}