C++ Vectors

The vector is a sequential container in the Standard Template Library (STL) of C++, used to store a collection of elements of the same type. It is dynamic in size, meaning that its size can be changed during the lifetime of the program, and provides fast and efficient access to elements, making it one of the most commonly used containers in C++.

Vectors are implemented as arrays that can grow and shrink in size, with all elements stored in contiguous memory. This makes vectors ideal for applications that require fast random access to elements, such as games and simulations. The size of a vector can be easily changed by using the push_back method to add elements to the end of the vector, or the pop_back method to remove elements from the end of the vector.

One of the key benefits of vectors is their ease of use. They can be used like arrays, but with the added benefits of dynamic sizing and automatic memory management. For example, to declare a vector of integers, you simply write:

vector<int> v;

Elements can be easily added to a vector using the push_back method:


And elements can be accessed using the array-style square bracket operator:

cout << v[0] << endl; // Outputs 10
cout << v[1] << endl; // Outputs 20

Vectors are also compatible with the algorithms and functions provided by the STL, making it easy to perform operations such as sorting, searching, and transforming the elements of a vector. For example, to sort a vector of integers, you can use the sort algorithm:

sort(v.begin(), v.end());

In addition to its ease of use, vectors are also highly efficient, with constant-time access to elements and amortized constant-time insertion and deletion at the end of the vector. This makes vectors ideal for use in performance-critical applications, such as games and simulations.

One important aspect to consider when using vectors is their memory management. Because vectors store elements in contiguous memory, resizing a vector can result in reallocating the entire vector, which can be time-consuming. To avoid this, it is recommended to reserve a suitable amount of memory for a vector before inserting elements, using the reserve method:


In conclusion, the vector is a versatile and powerful container in the STL of C++, offering ease of use, efficiency, and compatibility with the algorithms and functions provided by the STL. Whether you are writing a simple program or a complex simulation, vectors are a valuable tool for storing and manipulating collections of elements in C++.

Shubhajna Rai
Shubhajna Rai

A Civil Engineering Graduate interested to share valuable information with the aspirants.

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