How do I use std::remove_if with a lambda in C++?

Can you explain how to use std::remove_if with a lambda function in C++?

Sure! std::remove_if is used to remove elements from a container based on a condition. You can use a lambda function to define that condition.

Can you provide a code example?

Of course! Here's a simple example:

#include <vector>
#include <algorithm>
#include <iostream>

int main() {
    std::vector<int> numbers = {1, 2, 3, 4, 5, 6};
    numbers.erase(std::remove_if(numbers.begin(), numbers.end(), [](int n) { return n % 2 == 0; }), numbers.end());
    for (int n : numbers) {
        std::cout << n << ' ';
    }
}

This code removes all even numbers from the vector.

What does the lambda function do in this example?

The lambda function [](int n) { return n % 2 == 0; } checks if a number is even. If it is, std::remove_if will mark it for removal.

Is there a way to use std::remove_if without a lambda?

Yes, you can use a function pointer or a functor instead of a lambda. Would you like an example of that?