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

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

Answer

To get the first N items from a vector in C++, you can use the `std::vector` and iterator.

✐ Examples

1 Get First N Items from Vector

In this example,

First, you define a vector containing the elements from which you want to retrieve the first N items.
Next, you use iterators to specify the range for the first N items. C++ uses zero-based indexing, so to select the first N items, you iterate from the beginning to the Nth element.
Finally, you retrieve the elements within the specified range using iterators.

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;

    // Retrieve the first N items from the vector using iterators
    std::vector<int>::iterator it = vec.begin();
    std::vector<int>::iterator end = vec.begin() + N;

    // Print the first N items
    std::cout << "[ ";
    for (; it != end; ++it) {
        std::cout << *it << " ";
    }
    std::cout << "]" << std::endl;
    return 0;
}

Output

[ 1 2 3 4 5 ]

2 Get First Three Items from String Vector

In this example,

Define a vector containing strings.
Use iterators to specify the range from the beginning to the third element to retrieve the first three items from the string vector.
Retrieve the first three items within the specified range using iterators.

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"};

    // Specify the range to retrieve the first three items
    int range = 3;

    // Retrieve the first three items from the string vector using iterators
    std::vector<std::string>::iterator it = stringVector.begin();
    std::vector<std::string>::iterator end = stringVector.begin() + range;

    // Print the first three items
    std::cout << "[ ";
    for (; it != end; ++it) {
        std::cout << *it << " ";
    }
    std::cout << "]" << std::endl;
    return 0;
}

Output

[ apple banana orange ]

Summary

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

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

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

Answer

✐ Examples

1 Get First N Items from Vector

C++ Program

Output

2 Get First Three Items from String Vector

C++ Program

Output

Summary

More C++ Vectors Tutorials