How to get Last N Items from a Vector in C++ - Step by Step Examples

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How to get Last N Items from a Vector in C++ ?

Answer

To get the last N items from a vector in C++, you can use array slicing in combination with the size of the vector.

✐ Examples

1 Get Last N Items from Vector

In this example,

First, you define a vector containing the elements from which you want to retrieve the last N items.
Next, you calculate the starting index for the last N items by subtracting N from the size of the vector.
Finally, you retrieve the elements using array slicing with the calculated starting index to the end of the vector.

C++ Program

#include <iostream>
#include <vector>

int main() {
    // Define a vector containing elements
    std::vector<int> vec = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

    // Specify the number of items to retrieve (N)
    int N = 5;

    // Calculate the starting index for the last N items
    int start_index = vec.size() - N;

    // Retrieve the last N items from the vector using array slicing
    std::vector<int> last_N_items(vec.begin() + start_index, vec.end());

    // Print the last N items
    std::cout << "[ ";
    for (int i : last_N_items) {
        std::cout << i << " ";
    }
    std::cout << "]" << std::endl;
    return 0;
}

Output

[6 7 8 9 10]

2 Get Last Three Items from String Vector

In this example,

Define a vector containing strings.
Calculate the starting index for the last three items by subtracting three from the size of the string vector.
Retrieve the last three items using array slicing with the calculated starting index to the end of the string vector.

C++ Program

#include <iostream>
#include <vector>
#include <string>

int main() {
    // Define a vector containing strings
    std::vector<std::string> stringVector = {"apple", "banana", "orange", "grape", "kiwi"};

    // Calculate the starting index for the last three items
    int start_index = stringVector.size() - 3;

    // Retrieve the last three items from the string vector using array slicing
    std::vector<std::string> lastThreeItems(stringVector.begin() + start_index, stringVector.end());

    // Print the last three items
    std::cout << "[ ";
    for (const std::string& str : lastThreeItems) {
        std::cout << str << " ";
    }
    std::cout << "]" << std::endl;
    return 0;
}

Output

[orange banana apple ]

Summary

In this tutorial, we learned How to get Last N Items from a Vector in C++ language with well detailed examples.

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How to get Last N Items from a Vector in C++ - Step by Step Examples

How to get Last N Items from a Vector in C++ ?

Answer

✐ Examples

1 Get Last N Items from Vector

C++ Program

Output

2 Get Last Three Items from String Vector

C++ Program

Output

Summary

More C++ Vectors Tutorials