title: Clearing a Vector in C++ date: 2022-05-01 tags: #programming #Cplusplus —

When working with vectors in C++, it is often necessary to clear their contents. Clearing a vector means removing all elements from it, making it an empty vector. In this blog post, I will show you how to clear a vector in C++.

Using the clear() method

The simplest way to clear a vector is by using the clear() method provided by the standard vector class in C++. This method removes all elements from the vector, leaving it empty. Here’s an example:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> myVector = {1, 2, 3, 4, 5};

    // Clear the vector
    myVector.clear();

    // Check if the vector is empty
    if (myVector.empty()) {
        std::cout << "Vector is empty!" << std::endl;
    } else {
        std::cout << "Vector is not empty!" << std::endl;
    }

    return 0;
}

In the above example, we create a vector called myVector and initialize it with some values. Then, we call the clear() method to remove all elements from the vector. Finally, we use the empty() method to check if the vector is empty and print the appropriate message.

Removing elements by resizing the vector

Another way to clear a vector is by resizing it to a smaller size. When you resize a vector to a smaller size, any elements beyond the new size are automatically removed. Here’s an example:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> myVector = {1, 2, 3, 4, 5};

    // Resize the vector to 0
    myVector.resize(0);

    // Check if the vector is empty
    if (myVector.empty()) {
        std::cout << "Vector is empty!" << std::endl;
    } else {
        std::cout << "Vector is not empty!" << std::endl;
    }

    return 0;
}

In the above example, we create a vector called myVector and initialize it with some values. Then, we use the resize() method to resize the vector to a size of 0, effectively removing all elements. Again, we use the empty() method to check if the vector is empty and print the appropriate message.

Conclusion

In this blog post, we discussed two ways to clear a vector in C++. The clear() method and resizing the vector both serve the purpose of removing all elements from the vector. Depending on your specific use case, you can choose the method that best suits your needs. It’s always a good practice to clear a vector before reusing it to avoid any unexpected behavior.

Remember to use clear() or resize() when you need to remove all elements from a vector, and happy coding!

#programming #Cplusplus