How to Capture Pairs in Lambda Expression in C++?

How to Capture std::vector in Lambda Function?

Last Updated : 31 Jan, 2024

In C++, lambda functions allow users to define an inline function anywhere in the program. They are also able to capture the objects from outside its definition. In this article, we will look at how to capture a std::vector object in lambda functions in C++.

Capture std::vector in Lambda Function

To capture the std::vector container object that is present outside of the lambda function definition, we can use the capture clause of the lambda expression. The capture clause allows both capture by value and capture by reference method.

Capture by Value

[vector_name] (args){
    // code
}

Capture by Reference

[&vector_name] (args) {
    // code
}

C++ Program to Capture std::vector in Lambda Function

C++

// C++ program to capture std::vector in a lambda function
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

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

    // Lambda function capturing vector by reference
    auto printVector = [&vec]() mutable {
        for (auto elem : vec) {
            cout << elem << " ";
        }
        cout << endl;
    };

    // modifying vector by capturing using value
    auto addVectorV = [vec]() mutable{
        for (auto& elem : vec) {
            elem = elem + 1;
        }
    };

    // modifying vector by capturing using reference
    auto addVectorR = [&vec]() {
        for (auto& elem : vec) {
            elem = elem + 1;
        }
    };

    addVectorV();
    cout << "Original Vector after calling addVectorV: ";
    printVector();

    addVectorR();
    cout << "Original Vector after calling addVectorR: ";
    printVector();

    return 0;
}

Output

Original Vector after calling addVectorV: 1 2 3 4 5 
Original Vector after calling addVectorR: 2 3 4 5 6

How to Capture Pairs in Lambda Expression in C++?

A

ashish_rao_2373

Improve

Article Tags :

Practice Tags :

CPP

Similar Reads

How to Return a Vector From a Function in C++?

In C++, by returning vectors, users to return multiple values at once from a function as the elements of vector. In this article, we will learn how to return a vector from a function in C++.The recommended way to return a vector from a function is by using return vector by value method. Letâ€™s take a

How to Find the Mode of Vector in C++?

In C++, a vector is a dynamic array that resizes itself when needed. It also allows random access to its elements. In this article, we will learn how to find the mode of a vector in C++. The mode of a vector is the element that highest number of occurrences in the vector. Example: Input: myVector =

How to Find the Median of Sorted Vector in C++?

In C++, vectors are dynamic arrays and the median is a middle value when data is sorted in ascending order. In this article, we will learn how to find the median of all elements in a sorted vector in C++. Example Input: myVector = {10, 20, 30, 40, 50}; Output: Median is 30Finding Median of Sorted Ve

How to Capture Pairs in Lambda Expression in C++?

In C++, lambda expressions provide an easy way to define anonymous functions inline. They also allow these inline functions to capture some variables from the surrounding scope. In this article, we will learn how to capture pairs in lambda functions in C++ Capture Pairs in Lambda Expressions in C++W

How to Sort a Vector in a Map in C++?

In C++, we can create a map container where the values associated with keys is a vector. In this article, we will learn how to sort a vector within a map in C++. Example Input: myMap = { {3, {9, 7, 3}}, {5, {4, 2, 8, 1, 6}}, {8, {1, 2, 5, 8}} }; Output: Map: Key: 3, Sorted Vector: [3 7 9 ] Key: 5, S

How to Find the Capacity of a Vector in C++?

In C++, the capacity of a vector means the amount of space allocated for the vector, so the vector can hold more elements than its size without any reallocation of space. In this article, we will learn how to find the capacity of a vector in C++. Example: Input: myVector = {10,20,30}; Output: Capaci

How to Create a Function Template in C++?

In C++, templates enable us to write generic programs that handle any data type. We can create a template class, function, and variable. A template function is a function that can work with any data type. In this article, we will learn how to create a function template in C++. Create a Function Temp

How to Pass an Array into a Lambda Function in C++?

In C++, a lambda function, also known as a lambda expression, is a way of defining an anonymous function object right at the location where it is invoked or passed as an argument to a function. In this article, we will learn how to pass an array into a lambda function in C++. Passing an Array into a

How to use C++ Lambdas with Capture Clauses?

In C++, lambda expressions provide a convenient way to create one-liner functions. One of the key features of lambdas is their ability to capture variables from their surrounding scope by using capture clauses. This allows lambdas to access and modify variables from the outer scope, even after the l

How to Convert Map to a Vector of Pairs in C++?

In C++, map containers allow us to store the data in key-value pairs. There might be some cases where you want to convert an entire map into a vector of pairs. In this article, we will learn how to convert a map into a vector of pairs. Example Input: map<int,string>mp ={ {1,"one"}, {2,"two"},