How To Get The Size Of A Vector In C++

C++ vector size

Introduction to C++ vector size

In C++, Vectors are called dynamic arrays that can automatically resize themselves when an item is inserted or removed, with its storage being controlled automatically past the container. Vector items are kept in adjacent storage, which is piece of cake to admission and traverse with the assistance of iterators. Moreover, items are inserted at the end, and information technology may take some time every bit an extension of the array is needed in certain cases. There are several functions that support vector operations, and size() is one such function that helps in returning the vector size of the container or count of items available in it. In this topic, we are going to acquire about the C++ vector size.

Syntax

While learning a new concept in a programming language, yous have to empathise the same basic syntax. So, allow us come across the syntax of the size() role in vector.

vec.size()

Hither, vec is the proper noun of the vector

Parameters of the office:

Unlike other functions, no parameters are passed in this.

Return value:

Count of items in the container.

Exceptions and Errors

Do not guarantee exception throw.
When parameters are passed, errors are thrown.

How to find the size of vector work in C++?

Equally I have already mentioned, size() is one of the vector functions that help in returning the vector size of the container or count of items available in it.

For example, consider a vector vtr as mentioned beneath.

vector<int> vtr{31, 52, 63, 84, 57 };

From this, we tin can meet that there are 5 elements in the vector. Then, when we call the size() function, the effect will display the size of the vector as 5.

It can be used while performing addition operations in the vector. Instead of mentioning the size, the size() function can be used.

Examples of C++ vector size

Now, allow us meet some sample programs on the size function of vector in C++ for a better understanding.

Example #i

CPP program that demonstrates the implementation of size() function in vector

Code:

// C++ Plan to demonstrate the implementation of the role size() #include <iostream> #include <vector> using namespace std; //principal method int master() { //declare a vector vector<int> vtr{ 31, 52, 63, 84, 57 }; //impress the vector size cout <<"The vector size is: " << vtr.size(); return 0; }

Output:

First, this program imports all the necessary header files such equally <iostream> and <vector>. Later this, a vector is alleged with few elements. On executing the code, the size of the vector is printed using the size() function.

Example #2

CPP programme that uses size() function in vector for adding all the vector elements.

Lawmaking:

// C++ Plan that uses function size() for addition of vector elements #include <iostream> #include <vector> using namespace std; //main method int main() { //declare a variable to store the sum int due south = 0; //declare a vector vector<int> vtr{ 31, 52, 63, 84, 57 }; //print the vector size cout <<"The vector size is: " << vtr.size(); while (vtr.size() > 0) { south = southward + vtr.back(); vtr.pop_back(); } cout <<"\nSum of the vector elements is: " << south; return 0; }

Output:

C++ vector size output 2

In this plan, a vector is alleged with few elements and also, a variable southward is declared for storing the sum of the elements. On executing the lawmaking, the size of the vector is printed using the size() function, and the sum of the elements is printed using a for a loop.

Case #3

CPP program that uses size() function for a string vector

Code:

// C++ Program to demonstrate the implementation of the function size() in cord vector #include <iostream> #include <vector> using namespace std; //main method int chief() { //declare a vector vector<string> vtr{ " Practice not give up " , " Your miracle " , " on the ", " manner "} ; //variable to shop the vector size int s = vtr.size() ; //print the vector size cout <<"The vector size is: " << s ; return 0; }

Output:

In this plan, a vector is declared with string elements, unlike the higher up programs. But, the size() function prints the size of the vector.

Example #four

CPP program that creates an empty vector and prints the size

Code:

// C++ Program to create empty vector and print size #include <iostream> #include <vector> using namespace std; //primary method int chief() { //declare a vector std::vector<int> vtr; //variable to store the vector size int s = vtr.size() ; //impress the vector size cout <<"The vector size is: " << southward ; return 0; }

Output:

In this plan, a vector is declared with no elements, and on executing the code, the size of the vector volition be displayed every bit 0.

Example #5

CPP program that declares a vector add elements and impress size

Code:

#include <iostream> #include <vector> using namespace std; //main method int chief() { //declare a vector std::vector<int> vtr; //add the elements to the vector for (int i=0 ; i<five ; i++) { vtr.push_back(i); } //variable to store the vector size int south = vtr.size() ; //impress the vector size cout <<"The vector size is: " << s ; return 0; }

Output:

An empty vector is declared in this program, and elements are added to it using a for a loop. And then, the size of the vector is printed using the size() function.

Example #6

CPP program that inserts elements to vector cease and print size

Code:

#include <iostream> #include <vector> using namespace std; //principal method int chief() { //declare a vector std::vector<int> vtr; //add together the elements to the vector vtr.insert ( vtr.stop() , v, fifty ); //variable to shop the vector size int s = vtr.size() ; //impress the vector size cout <<"The vector size is: " << southward ; render 0; }

Output:

In this programme also, an empty vector is declared first, and elements are added to the cease of the vector using insert(). Then, the size of the vector is printed using the size() part.

Determination

size() is a method that helps in returning the vector size of the container or count of items bachelor in a vector. In this commodity, different aspects such every bit syntax, working, and examples of size() function are explained in detail.