C++ Vector

duction to C++ Vector

In C++, a vector is a dynamic array that can grow or shrink in size. It is part of the Standard Template Library (STL) and provides a flexible and efficient way to store and manipulate collections of elements. Vectors are commonly used in C++ programming due to their versatility and ease of use.

Creating a Vector

To create a vector in C++, you need to include the <vector> header file. Here’s an example of how to create a vector:

#include <vector>
using namespace std;

int main() {
    // Create an empty vector
    vector<int> numbers;

    // Add elements to the vector
    numbers.push_back(10);
    numbers.push_back(20);
    numbers.push_back(30);

    return 0;
}

In the above example, we create an empty vector called “numbers” using the vector<int> syntax. We then use the push_back() function to add elements to the vector. The vector automatically resizes itself to accommodate the new elements.

Accessing Elements in a Vector

You can access elements in a vector using the square bracket notation ([]). Here’s an example:

#include <vector>
#include <iostream>
using namespace std;

int main() {
    vector<string> fruits;
    fruits.push_back("Apple");
    fruits.push_back("Banana");
    fruits.push_back("Orange");

    // Accessing elements
    cout << fruits[0] << endl;  // Output: Apple
    cout << fruits[1] << endl;  // Output: Banana
    cout << fruits[2] << endl;  // Output: Orange

    return 0;
}

In the above example, we create a vector called “fruits” and add three elements to it. We then use the square bracket notation to access and print the elements of the vector.

Iterating Over a Vector

You can use a loop to iterate over the elements of a vector. Here’s an example:

#include <vector>
#include <iostream>
using namespace std;

int main() {
    vector<int> numbers;
    numbers.push_back(1);
    numbers.push_back(2);
    numbers.push_back(3);

    // Iterating over the vector
    for (int i = 0; i < numbers.size(); i++) {
        cout << numbers[i] << endl;
    }

    return 0;
}

In the above example, we create a vector called “numbers” and add three elements to it. We then use a for loop to iterate over the vector and print each element.

Vector Operations

C++ vectors provide various operations to manipulate and modify the elements. Here are some commonly used operations:

• push_back(element): Adds an element to the end of the vector.
• pop_back(): Removes the last element from the vector.
• insert(iterator, element): Inserts an element at a specified position in the vector.
• erase(iterator): Removes an element at a specified position from the vector.
• size(): Returns the number of elements in the vector.
• empty(): Checks if the vector is empty.
• clear(): Removes all elements from the vector.

Here’s an example that demonstrates some of these operations:

#include <vector>
#include <iostream>
using namespace std;

int main() {
    vector<int> numbers;
    numbers.push_back(1);
    numbers.push_back(2);
    numbers.push_back(3);

    // Inserting an element at position 1
    numbers.insert(numbers.begin() + 1, 4);

    // Removing the element at position 2
    numbers.erase(numbers.begin() + 2);

    // Printing the elements
    for (int i = 0; i < numbers.size(); i++) {
        cout << numbers[i] << endl;
    }

    return 0;
}

In the above example, we add three elements to the vector “numbers”. We then insert an element at position 1 using the insert() function and remove the element at position 2 using the erase() function. Finally, we iterate over the vector and print its elements.

Conclusion

C++ vectors are a powerful tool for managing collections of elements. They provide a flexible and efficient way to store, access, and manipulate data. By understanding how to create and use vectors, you can enhance your C++ programming skills and build more robust applications.