How to Remove Element from List based on a Condition in C++ - Step by Step Examples

How to Remove Element from List based on a Condition in C++ ?

Answer

To remove elements from a list in C++ using `std::list`, you can use the `remove_if` algorithm along with a lambda function.

✐ Examples

1 Remove Elements Greater Than a Threshold

In this example,

We include the necessary headers for using std::list and algorithms.
We create a list named numbers with some elements.
We specify the threshold value.
We use the remove_if algorithm along with a lambda function to remove elements greater than the threshold.
Finally, we print the modified list to standard output.

C++ Program

#include <iostream>
#include <list>
#include <algorithm>

int main() {
    std::list<int> numbers = {1, 2, 3, 4, 5};
    int threshold = 3;
    numbers.remove_if([&threshold](int x) { return x > threshold; });
    for (const auto& num : numbers) {
        std::cout << num << " ";
    }
    return 0;
}

Output

1 2 3

2 Remove Elements Matching a Predicate

In this example,

We include the necessary headers for using std::list and algorithms.
We create a list named names with some elements.
We define a predicate function is_long_name that returns true if the length of the string is greater than a specified value.
We use the remove_if algorithm along with the is_long_name predicate to remove elements matching the predicate condition.
Finally, we print the modified list to standard output.

C++ Program

#include <iostream>
#include <list>
#include <algorithm>

bool is_long_name(const std::string& name, int max_length) {
    return name.length() > max_length;
}

int main() {
    std::list<std::string> names = {"John", "Alice", "Michael", "Emma"};
    int max_length = 5;
    names.remove_if([&max_length](const std::string& name) { return is_long_name(name, max_length); });
    for (const auto& name : names) {
        std::cout << name << " ";
    }
    return 0;
}

Output

John Alice Emma

Summary

In this tutorial, we learned How to Remove Element from List based on a Condition in C++ language with well detailed examples.

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How to Remove Element from List based on a Condition in C++ - Step by Step Examples

How to Remove Element from List based on a Condition in C++ ?

Answer

✐ Examples

1 Remove Elements Greater Than a Threshold

C++ Program

Output

2 Remove Elements Matching a Predicate

C++ Program

Output

Summary

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