Lære What Are Lambdas and Why They Exist | Introduction to Lambda Expressions

Forudsætninger

C++ Functions

Definition

A lambda expression is a concise way to define an anonymous function directly in your code. Lambdas let you write small, inline functions at the point where you need them, often as arguments to algorithms or for encapsulating brief logic.

Before lambda expressions, C++ developers used function pointers and functors to pass behavior to algorithms. Function pointers were simple but lacked type safety and couldn’t capture local variables. Functors could hold state but required defining extra structs or classes, making the code verbose.

main.cpp


              1234567891011121314
            
#include <iostream>

// Traditional function pointer
void printMessage()
{
    std::cout << "Hello from function pointer!" << std::endl;
}

int main()
{
    // Using a function pointer
    void (*funcPtr)() = printMessage;
    funcPtr();
}

Lambda expressions solved these issues by offering concise, inline functions that can capture local variables, improving readability and flexibility.

main.cpp


              1234567891011
            
#include <iostream>

int main()
{
    // Using a lambda expression
    auto lambda = []() {
        std::cout << "Hello from lambda!" << std::endl;
    };

    lambda();
}

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Forudsætninger

C++ Functions

Definition

main.cpp


              1234567891011121314
            
#include <iostream>

// Traditional function pointer
void printMessage()
{
    std::cout << "Hello from function pointer!" << std::endl;
}

int main()
{
    // Using a function pointer
    void (*funcPtr)() = printMessage;
    funcPtr();
}

Lambda expressions solved these issues by offering concise, inline functions that can capture local variables, improving readability and flexibility.

main.cpp


              1234567891011
            
#include <iostream>

int main()
{
    // Using a lambda expression
    auto lambda = []() {
        std::cout << "Hello from lambda!" << std::endl;
    };

    lambda();
}

Var alt klart?

Tak for dine kommentarer!

Sektion 1. Kapitel 1