In programming, a vector is a dynamic array that can grow or shrink in size as needed. Resizing a vector is a common operation that allows us to add or remove elements from the vector based on our requirements. In this blog post, we will explore how to resize a vector in different programming languages.

C++

In C++, the standard library provides the std::vector class which simplifies the process of resizing a vector. To resize a vector, we can use the resize() member function. Here’s an example:

#include <vector>

int main() {
    std::vector<int> numbers;
    
    // Add elements to the vector
    numbers.push_back(1);
    numbers.push_back(2);
    numbers.push_back(3);
    
    // Resize the vector to contain 5 elements
    numbers.resize(5);
    
    return 0;
}

The resize() function takes an integer argument specifying the new size of the vector. If the new size is larger than the current size, additional elements are added with default values. If the new size is smaller, the extra elements are removed from the end of the vector.

Python

In Python, list objects can be resized dynamically without any additional steps. Here’s an example:

numbers = []

# Add elements to the list
numbers.append(1)
numbers.append(2)
numbers.append(3)

# Resize the list to contain 5 elements
numbers = numbers + [None] * 2

In this example, we concatenate the original list with a list of None values multiplied by the desired number of elements to be added. This effectively resizes the list by adding elements to the end.

JavaScript

In JavaScript, arrays can be resized using the length property. Here’s an example:

let numbers = [];

// Add elements to the array
numbers.push(1);
numbers.push(2);
numbers.push(3);

// Resize the array to contain 5 elements
numbers.length = 5;

Setting the length property to a new value resizes the array. If the new length is larger than the current length, additional elements are added with empty values. If the new length is smaller, the extra elements are removed from the end of the array.

Conclusion

Resizing a vector or an array is a useful operation that allows us to manipulate the size dynamically based on our needs. Whether you are working with C++, Python, or JavaScript, the process of resizing vectors or arrays is straightforward and can be easily implemented.